diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ecb3b9fa..0e6b50c8 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -46,6 +46,8 @@ jobs:
           - mksgenlv1
           - esp32
           - ramps
+          - rp2040_jackw01
+          - rp2040_skr_pico
     steps:
       - uses: actions/checkout@v6
       - uses: ./.github/actions/setup-pio
diff --git a/.gitignore b/.gitignore
index 84f88302..b0686c2e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -10,10 +10,9 @@ CMakeListsPrivate.txt
 build_cache
 
 Configuration_local*
-MeadeToWikiOutput.txt
-
 !Configuration_local_examples/
 !Configuration_local_examples/*
+MeadeToWikiOutput.txt
 
 # macOS
 **/.DS_Store
diff --git a/Configuration.hpp b/Configuration.hpp
index 353208bd..b348dd68 100644
--- a/Configuration.hpp
+++ b/Configuration.hpp
@@ -64,10 +64,24 @@
         #define INFO_DISPLAY_I2C_ADDRESS 0x3C
     #endif
     #ifndef INFO_DISPLAY_I2C_SDA_PIN
-        #define INFO_DISPLAY_I2C_SDA_PIN 5
+        #if (BOARD == BOARD_RP2040_SKR_PICO)
+            // The SKR Pico has exactly one header-accessible I2C-capable GPIO pair:
+            // GP0/GP1 on the left-side header (shared with the default GPS wiring).
+            #define INFO_DISPLAY_I2C_SDA_PIN 0
+        #elif (BOARD == BOARD_RP2040_JACKW01)
+            #define INFO_DISPLAY_I2C_SDA_PIN 20
+        #else
+            #define INFO_DISPLAY_I2C_SDA_PIN 5
+        #endif
     #endif
     #ifndef INFO_DISPLAY_I2C_SCL_PIN
-        #define INFO_DISPLAY_I2C_SCL_PIN 4
+        #if (BOARD == BOARD_RP2040_SKR_PICO)
+            #define INFO_DISPLAY_I2C_SCL_PIN 1
+        #elif (BOARD == BOARD_RP2040_JACKW01)
+            #define INFO_DISPLAY_I2C_SCL_PIN 21
+        #else
+            #define INFO_DISPLAY_I2C_SCL_PIN 4
+        #endif
     #endif
     #ifndef INFO_DISPLAY_UPSIDE_DOWN
         #define INFO_DISPLAY_UPSIDE_DOWN 0
@@ -164,7 +178,12 @@
  * See Constants.hpp for predefined SERIAL_BAUDRATE options, or customize as required.
  */
 #ifndef SERIAL_BAUDRATE
-    #define SERIAL_BAUDRATE SERIAL_BAUDRATE_ASCOM
+    #if defined(ARDUINO_ARCH_RP2040)
+        // The 19200 ASCOM default exists because the 8-bit AVR platforms cannot keep up.
+        #define SERIAL_BAUDRATE SERIAL_BAUDRATE_FAST
+    #else
+        #define SERIAL_BAUDRATE SERIAL_BAUDRATE_ASCOM
+    #endif
 #endif
 
 /**
diff --git a/ConfigurationValidation.hpp b/ConfigurationValidation.hpp
index 190d306e..386bb1cf 100644
--- a/ConfigurationValidation.hpp
+++ b/ConfigurationValidation.hpp
@@ -174,6 +174,17 @@
     #error Unsupported GPS configuration. Use at own risk.
 #endif
 
+// RP2040 SKR Pico: info display pin sharing.
+#if defined(ARDUINO_ARCH_RP2040) && (BOARD == BOARD_RP2040_SKR_PICO) && (INFO_DISPLAY_TYPE != INFO_DISPLAY_TYPE_NONE)
+    #if (USE_GPS == 1)
+        #error On the SKR Pico the info display and GPS share GP0/GP1 on the left-side header. Enable only one, or remap the pins explicitly.
+    #endif
+    #if (INFO_DISPLAY_I2C_SDA_PIN == 20) || (INFO_DISPLAY_I2C_SCL_PIN == 21) || (INFO_DISPLAY_I2C_SDA_PIN == 21)                           \
+        || (INFO_DISPLAY_I2C_SCL_PIN == 20)
+        #error GP20/GP21 on the SKR Pico only drive on-board MOSFETs (HB/FAN/Laser power outputs); they are not exposed as GPIO on any connector and cannot be used for I2C. Use GP0/GP1 on the left-side header.
+    #endif
+#endif
+
 #if (USE_GYRO_LEVEL == 0)
 // Baseline configuration without gyro is valid
 #elif defined(ESP32) || defined(__AVR_ATmega2560__)
@@ -240,12 +251,6 @@
             // Required pin assignments missing (ATmega uses SoftwareSerial for this driver)
             #error Missing pin assignments for configured AZ DRIVER_TYPE_TMC2209_UART driver
         #endif
-        #if !defined(AZ_DIAG_PIN)
-            // AZ_DIAG_PIN (TMC2209 DIAG output) is used only for stallGuard-based homing.
-            // It is optional: omit it if your hardware does not wire the DIAG output to a GPIO.
-            // Without it, stallGuard homing is unavailable but all other AZ motion works normally.
-            #pragma message "AZ_DIAG_PIN not defined. StallGuard homing unavailable for AZ axis."
-        #endif
         #if !((defined(AZ_SERIAL_PORT_TX) && defined(AZ_SERIAL_PORT_RX)) || defined(AZ_SERIAL_PORT))
             // Required pin assignments missing for UART serial
             #error Missing pin assignments for configured AZ DRIVER_TYPE_TMC2209_UART driver serial connection
@@ -264,12 +269,6 @@
             // Required pin assignments missing (ATmega uses SoftwareSerial for this driver)
             #error Missing pin assignments for configured ALT DRIVER_TYPE_TMC2209_UART driver
         #endif
-        #if !defined(ALT_DIAG_PIN)
-            // ALT_DIAG_PIN (TMC2209 DIAG output) is used only for stallGuard-based homing.
-            // It is optional: omit it if your hardware does not wire the DIAG output to a GPIO.
-            // Without it, stallGuard homing is unavailable but all other ALT motion works normally.
-            #pragma message "ALT_DIAG_PIN not defined. StallGuard homing unavailable for ALT axis."
-        #endif
         #if !((defined(ALT_SERIAL_PORT_TX) && defined(ALT_SERIAL_PORT_RX)) || defined(ALT_SERIAL_PORT))
             // Required pin assignments missing for UART serial
             #error Missing pin assignments for configured ALT DRIVER_TYPE_TMC2209_UART driver serial connection
diff --git a/Configuration_adv.hpp b/Configuration_adv.hpp
index 48d87f7f..07b480b0 100644
--- a/Configuration_adv.hpp
+++ b/Configuration_adv.hpp
@@ -35,6 +35,19 @@
 //                            ////////
 // MOTOR & DRIVER SETTINGS    ////////
 //                            ////////
+//////////////////////////////////////
+//
+// Interval at which the stepper control timer/interrupt services the steppers.
+// Shorter intervals mean finer step timing. AVR is capped at 2 kHz: higher rates
+// there interfere with serial communications. The RP2040 has ample headroom.
+#ifndef STEPPER_CONTROL_INTERVAL_MS
+    #if defined(ARDUINO_ARCH_RP2040)
+        #define STEPPER_CONTROL_INTERVAL_MS 0.2f  // 5 kHz
+    #else
+        #define STEPPER_CONTROL_INTERVAL_MS 0.5f  // 2 kHz
+    #endif
+#endif
+
 //////////////////////////////////////
 //
 // This is how many steps your stepper needs for a full rotation.
@@ -556,16 +569,15 @@
 // Enable RA End Switches in your local configuration. Do not edit here!
 #ifndef USE_RA_END_SWITCH
     #define USE_RA_END_SWITCH 0
-#else
-    #ifndef RA_END_SWITCH_ACTIVE_STATE
-        #define RA_END_SWITCH_ACTIVE_STATE LOW
-    #endif
-    // You can define how many degrees to slew back after the end switch has triggered.
-    // Mechanical end switches might have a hysteresis behavior, meaning once signaled,
-    // it needs to move well back beyond the signal point to become un-signaled.
-    #ifndef RA_ENDSWITCH_BACKSLEW_DEG
-        #define RA_ENDSWITCH_BACKSLEW_DEG 0.5
-    #endif
+#endif
+#ifndef RA_END_SWITCH_ACTIVE_STATE
+    #define RA_END_SWITCH_ACTIVE_STATE LOW
+#endif
+// You can define how many degrees to slew back after the end switch has triggered.
+// Mechanical end switches might have a hysteresis behavior, meaning once signaled,
+// it needs to move well back beyond the signal point to become un-signaled.
+#ifndef RA_ENDSWITCH_BACKSLEW_DEG
+    #define RA_ENDSWITCH_BACKSLEW_DEG 0.5
 #endif
 
 //////////////////////////////////////////
@@ -574,17 +586,15 @@
 // Enable DEC End Switches in your local configuration. Do not edit here!
 #ifndef USE_DEC_END_SWITCH
     #define USE_DEC_END_SWITCH 0
-#else
-    #ifndef DEC_END_SWITCH_ACTIVE_STATE
-        #define DEC_END_SWITCH_ACTIVE_STATE LOW
-    #endif
-    // You can define how many degrees to slew back after the end switch has triggered.
-    // Mechanical end switches might have a hysteresis behavior, meaning once signaled,
-    // it needs to move well back beyond the signal point to become un-signaled.
-    #ifndef DEC_ENDSWITCH_BACKSLEW_DEG
-        #define DEC_ENDSWITCH_BACKSLEW_DEG 0.5
-    #endif
-
+#endif
+#ifndef DEC_END_SWITCH_ACTIVE_STATE
+    #define DEC_END_SWITCH_ACTIVE_STATE LOW
+#endif
+// You can define how many degrees to slew back after the end switch has triggered.
+// Mechanical end switches might have a hysteresis behavior, meaning once signaled,
+// it needs to move well back beyond the signal point to become un-signaled.
+#ifndef DEC_ENDSWITCH_BACKSLEW_DEG
+    #define DEC_ENDSWITCH_BACKSLEW_DEG 0.5
 #endif
 
 //////////////////////////////////////////
diff --git a/Configuration_local_examples/Configuration_local_rp2040_skr_pico.hpp b/Configuration_local_examples/Configuration_local_rp2040_skr_pico.hpp
index a757cfe5..2fbe97ac 100644
--- a/Configuration_local_examples/Configuration_local_rp2040_skr_pico.hpp
+++ b/Configuration_local_examples/Configuration_local_rp2040_skr_pico.hpp
@@ -16,7 +16,7 @@
  *  Stepper slot : E0 -> ALT   (TMC2209, UART addr 3)
  *  Motor rating : 0.9 deg / step (400 SPR), 470 mA
  *  Pulley       : 16T aluminium GT2
- *  RA homing    : Hall sensor on GPIO4 (X-STOP / RA_DIAG_PIN)
+ *  RA homing    : Hall sensor on GPIO4 (X-STOP)
  *
  * All pin assignments are in boards/RP2040_SKR_PICO/pins_RP2040_SKR_PICO.hpp.
  * R_SENSE (0.11 ohm) is set globally in src/a_inits.hpp for all TMC2209_UART
@@ -124,15 +124,25 @@
 #endif
 
 // ── RA Hall sensor auto-home ──────────────────────────────────────────────────
-// Hall sensor is wired to GPIO4 (X-STOP input / RA_DIAG_PIN on SKR Pico).
+// Hall sensor is wired to GPIO4 (X-STOP input on SKR Pico).
 // Active state LOW: sensor pulls GPIO4 LOW when the magnet is present.
 // Search distance: 30° default (RA_HOMING_SENSOR_SEARCH_DEGREES in Configuration_adv.hpp).
 // GPIO4 is configured INPUT (no pull-up); add external 10kΩ to 3.3V if sensor
 // is open-drain, or change to INPUT_PULLUP in b_setup.hpp.
 #define USE_HALL_SENSOR_RA_AUTOHOME   1
-#define RA_HOMING_SENSOR_PIN          4    // GPIO4 = RA_DIAG_PIN (X-STOP)
+#define RA_HOMING_SENSOR_PIN          4    // GPIO4 (X-STOP)
 #define RA_HOMING_SENSOR_ACTIVE_STATE LOW  // sensor pulls LOW when active
 
+// ── Info display (alternative to GPS) ─────────────────────────────────────────
+// The SKR Pico has exactly one header-accessible I2C-capable GPIO pair: GP0/GP1
+// on the left-side header (IO0/IO1/GND/5V). This example uses it for GPS below.
+// For an SSD1306 128x64 info display instead, set USE_GPS to 0 and enable:
+//   #define INFO_DISPLAY_TYPE INFO_DISPLAY_TYPE_I2C_SSD1306_128x64
+//   (SDA/SCL then default to GP0/GP1: SDA->IO0, SCL->IO1, VCC->5V, GND->GND.)
+// NOTE: GP20/GP21 must NOT be used for the display on this board - they only
+// drive the HB/FAN/Laser MOSFET power outputs and never reach a connector as
+// raw GPIO (wiring I2C there hangs the bus). Enforced by ConfigurationValidation.
+
 // ── GPS ───────────────────────────────────────────────────────────────────────
 // ATGM336H-5N wired to left-side header: GPS TX→IO1, GPS RX→IO0, VCC→5V, GND.
 // GPS_SERIAL_PORT, RP2040_GPS_TX_PIN, RP2040_GPS_RX_PIN defined in pins file.
diff --git a/Constants.hpp b/Constants.hpp
index 56ccb6ce..f0ef8b40 100644
--- a/Constants.hpp
+++ b/Constants.hpp
@@ -21,7 +21,9 @@
 #define BOARD_ESP32_ESP32DEV 1001
 #define BOARD_OAE_V1         1002
 
-// RP2040 based boards
+// RP2040 based boards (2000-2999)
+//   2101-2199: Pico family + JackW01 printer carrier board
+//   2201-2299: BTT SKR Pico family
 #define BOARD_RP2040_JACKW01  2101
 #define BOARD_RP2040_SKR_PICO 2201
 
@@ -67,6 +69,7 @@
 
 // USB serial port speed according to external controller
 #define SERIAL_BAUDRATE_ASCOM 19200
+#define SERIAL_BAUDRATE_FAST  115200  // For platforms that keep up (RP2040 USB CDC)
 
 // Wifi operating modes (ESP32 only)
 #define WIFI_MODE_INFRASTRUCTURE 0  // Infrastructure Only - OAT connects to an existing Router
diff --git a/Example_Configuration_local_rp2040_skr_pico.hpp b/Example_Configuration_local_rp2040_skr_pico.hpp
new file mode 100644
index 00000000..edd4f73d
--- /dev/null
+++ b/Example_Configuration_local_rp2040_skr_pico.hpp
@@ -0,0 +1,143 @@
+/**
+ * @brief Bench configuration for the BTT SKR Pico v1.0 RP2040 board.
+ *
+ * Personal local config (gitignored). Based on
+ * Configuration_local_examples/Configuration_local_rp2040_skr_pico.hpp,
+ * adapted for the bench hardware:
+ *   - Hall homing sensors on RA (X-STOP GPIO4) AND DEC (Y-STOP GPIO3)
+ *   - DEC endstops on Z-STOP (GPIO25, down) and E-STOP (GPIO16, up)
+ *   - SSD1306 info display on I2C0, GP0/GP1 on the left-side header
+ *   - GPS disabled for the bench
+ *
+ * All other pin assignments are in boards/RP2040_SKR_PICO/pins_RP2040_SKR_PICO.hpp.
+ */
+#pragma once
+
+// ── Board ─────────────────────────────────────────────────────────────────────
+#define BOARD BOARD_RP2040_SKR_PICO
+#define OAM
+#define TEST_VERIFY_MODE 0
+
+// ── Hemisphere ────────────────────────────────────────────────────────────────
+#define NORTHERN_HEMISPHERE 1
+
+// ── Display ────────────────────────────────────────────────────────────────────
+// No LCD menu display (RP2040 phase 1); SSD1306 128x64 info display on I2C0.
+// GP0/GP1 on the left-side header (IO0/IO1/GND/5V) - the only header-accessible
+// I2C0 pair on the SKR Pico. Shares pins with the default GPS wiring, so
+// USE_GPS must stay 0 while the display is enabled.
+// (GP20/GP21 are MOSFET-gate-only nets on this board - HB/FAN/Laser outputs,
+// never exposed as raw GPIO; wiring I2C there hangs the bus and the firmware.)
+#define DISPLAY_TYPE             DISPLAY_TYPE_NONE
+#define INFO_DISPLAY_TYPE        INFO_DISPLAY_TYPE_I2C_SSD1306_128x64
+#define INFO_DISPLAY_I2C_ADDRESS 0x3C
+#define INFO_DISPLAY_I2C_SDA_PIN 0  // GP0 (I2C0 SDA, left header IO0)
+#define INFO_DISPLAY_I2C_SCL_PIN 1  // GP1 (I2C0 SCL, left header IO1)
+#define INFO_DISPLAY_UPSIDE_DOWN 1
+#define INFO_DISPLAY_MIRRORED    0
+
+// ── Stepper control interval ─────────────────────────────────────────────────
+// 5 kHz is the RP2040 default (see Configuration_adv.hpp) and the bench-verified
+// rate. The RP2040 can also handle 10 kHz if you need faster step generation
+// (set 0.1f), but that is not part of the verified baseline.
+#define STEPPER_CONTROL_INTERVAL_MS 0.2f  // 5 kHz
+
+// ── Stepper motor types ───────────────────────────────────────────────────────
+#define RA_STEPPER_TYPE  STEPPER_TYPE_ENABLED
+#define DEC_STEPPER_TYPE STEPPER_TYPE_ENABLED
+#define AZ_STEPPER_TYPE  STEPPER_TYPE_ENABLED
+#define ALT_STEPPER_TYPE STEPPER_TYPE_ENABLED
+
+// ── Stepper driver types ──────────────────────────────────────────────────────
+#define RA_DRIVER_TYPE  DRIVER_TYPE_TMC2209_UART
+#define DEC_DRIVER_TYPE DRIVER_TYPE_TMC2209_UART
+#define AZ_DRIVER_TYPE  DRIVER_TYPE_TMC2209_UART
+#define ALT_DRIVER_TYPE DRIVER_TYPE_TMC2209_UART
+
+// ── RA Settings ───────────────────────────────────────────────────────────────
+#define RA_SLEW_MICROSTEPPING        16   // µsteps used while slewing RA
+#define RA_TRACKING_MICROSTEPPING    256  // µsteps used for sidereal tracking
+#define RA_STEPPER_SPEED             8000  // steps/s. If SPEED and ACCELERATION numbers are the same, the spool up to full speed takes one second.
+#define RA_STEPPER_ACCELERATION      8000      // steps/s/s
+#define RA_MOTOR_CURRENT_RATING      1000      // mA
+#define RA_OPERATING_CURRENT_SETTING 75        // %
+#define RA_WHEEL_CIRCUMFERENCE       1130.97f  // 360mm diam
+#define RA_PULLEY_TEETH              16
+#define RA_STEPPER_SPR               (400 * 9)  // change to (200 * 9) for 1.8° stepper
+#define RA_LIMIT_LEFT                6.0f
+#define RA_LIMIT_RIGHT               6.0f
+#define RA_INVERT_DIR                1
+
+// ── DEC settings ────────────────────────────────────────────────────────────
+#define DEC_SLEW_MICROSTEPPING        16   // µsteps used while slewing DEC
+#define DEC_GUIDE_MICROSTEPPING       256  // µsteps used for guide pulses
+#define DEC_STEPPER_SPEED             8000  // steps/s. If SPEED and ACCELERATION numbers are the same, the spool up to full speed takes one second.
+#define DEC_STEPPER_ACCELERATION      8000  // steps/s/s
+#define DEC_MOTOR_CURRENT_RATING      1000  // mA
+#define DEC_OPERATING_CURRENT_SETTING 75    // %
+#define DEC_WHEEL_CIRCUMFERENCE       816.814f
+#define DEC_PULLEY_TEETH              16
+#define DEC_STEPPER_SPR               (400 * 9)  // change to (200 * 9) for 1.8° stepper
+#define DEC_LIMIT_UP                  130
+#define DEC_LIMIT_DOWN                130
+#define DEC_INVERT_DIR                1
+
+// ── StealthChop (silent mode) ─────────────────────────────────────────────────
+#define RA_UART_STEALTH_MODE  1
+#define DEC_UART_STEALTH_MODE 1
+
+// ── AZIMUTH definitions ──────────────────────────────────────────────────────
+#define AZ_MICROSTEPPING             16
+#define AZ_STEPPER_SPEED             2500
+#define AZ_STEPPER_ACCELERATION      1250
+#define AZ_MOTOR_CURRENT_RATING      2000  // mA
+#define AZ_OPERATING_CURRENT_SETTING 80    // %
+#define AZ_STEPPER_SPR               400
+#define AZ_ALWAYS_ON                 1
+#define AZ_MOTOR_HOLD_SETTING        15
+#define AZ_PULLEY_TEETH              20
+#define AZ_ROD_PITCH                 1.0f  // mm per full rev of stepper
+#define AZ_CIRCUMFERENCE             (115 * 2 * 3.1415927)
+#define AZIMUTH_STEPS_PER_REV        (AZ_CIRCUMFERENCE / AZ_ROD_PITCH * AZ_STEPPER_SPR * AZ_MICROSTEPPING)  // Steps needed to turn AZ 360deg
+#define AZ_INVERT_DIR                1
+
+// ── ALTITUDE definitions ─────────────────────────────────────────────────────
+#define ALT_MICROSTEPPING             32
+#define ALT_STEPPER_SPEED             2500
+#define ALT_STEPPER_ACCELERATION      1250
+#define ALT_MOTOR_CURRENT_RATING      1000  // mA
+#define ALT_OPERATING_CURRENT_SETTING 70    // %
+#define ALT_STEPPER_SPR               400
+#define ALT_INVERT_DIR                0
+#define ALT_ALWAYS_ON                 0
+
+// ── Hall sensor auto-homing (RA and DEC) ──────────────────────────────────────
+// RA sensor on X-STOP (GPIO4 = RA_DIAG_PIN), DEC sensor on Y-STOP (GPIO3 = DEC_DIAG_PIN).
+// Active state LOW: sensor pulls the GPIO LOW when the magnet is present.
+#define USE_HALL_SENSOR_RA_AUTOHOME   0
+#define RA_HOMING_SENSOR_PIN          4  // GPIO4 = X-STOP
+#define RA_HOMING_SENSOR_ACTIVE_STATE LOW
+
+#define USE_HALL_SENSOR_DEC_AUTOHOME   0
+#define DEC_HOMING_SENSOR_PIN          3  // GPIO3 = Y-STOP
+#define DEC_HOMING_SENSOR_ACTIVE_STATE LOW
+
+// ── DEC endstops ──────────────────────────────────────────────────────────────
+// Wired to the two remaining endstop inputs on the SKR Pico.
+#define USE_DEC_END_SWITCH            0
+#define DEC_ENDSWITCH_DOWN_SENSOR_PIN 25  // GPIO25 = Z-STOP
+#define DEC_ENDSWITCH_UP_SENSOR_PIN   16  // GPIO16 = E-STOP
+#define DEC_END_SWITCH_ACTIVE_STATE   LOW
+
+// ── GPS ───────────────────────────────────────────────────────────────────────
+// Disabled for the bench (no module connected). NOTE: GPS shares GP0/GP1 with
+// the info display on this board - only one of the two can be enabled.
+#define USE_GPS 0
+
+// ── FAN (disabled for now)───────────────────────────────────────────────────────────────────────
+// #define RP2040_FAN1_POWER_PERCENT 60
+
+// Track immediately after boot
+#define TRACK_ON_BOOT 0
+
+#define DEBUG_LEVEL (DEBUG_NONE)
diff --git a/docs/RP2040-WIRING.md b/docs/RP2040-WIRING.md
new file mode 100644
index 00000000..f9c0ea23
--- /dev/null
+++ b/docs/RP2040-WIRING.md
@@ -0,0 +1,176 @@
+# RP2040 Wiring Guide
+
+Pin assignments for the two RP2040 boards supported by the OpenAstroTracker
+firmware:
+
+| Board | Board ID | Pins file |
+|---|---|---|
+| BigTreeTech **SKR Pico v1.0** | `BOARD_RP2040_SKR_PICO` (2201) | `boards/RP2040_SKR_PICO/pins_RP2040_SKR_PICO.hpp` |
+| **JackW01** (pi-pico-printer-board carrier) | `BOARD_RP2040_JACKW01` (2101) | `boards/RP2040_JACKW01/pins_RP2040_JACKW01.hpp` |
+
+Everything below reflects the **default** pin mapping compiled into the
+firmware. Peripherals are enabled in your `Configuration_local_*.hpp` (see
+`Configuration_local_examples/Configuration_local_rp2040_skr_pico.hpp` for a
+complete annotated example). GPIO numbers refer to the `GPxx` labels on the
+board, not to physical pin positions.
+
+All GPIO signals are **3.3 V logic**.
+
+---
+
+## Power (SKR Pico)
+
+The board can be powered from USB, from the VIN terminals (12-24 V), or both -
+but **never leave the USB-power jumper on while VIN is applied**. The jumper
+ties the 5 V rail to USB VBUS; with a supply also feeding the rail, the
+contention can hang the board during stepper driver initialization. Use:
+
+- **Jumper removed + VIN (12-24 V)** - normal operation. Motors and drivers are
+  powered, and the USB connector still works for flashing and serial (its data
+  lines are independent of VBUS).
+- **USB only (jumper fitted)** - the firmware boots and serial works, but the
+  stepper drivers have no motor power; nothing moves.
+
+## Stepper motors
+
+Drivers must be `DRIVER_TYPE_TMC2209_UART` (the boards carry no A4988/standalone
+wiring - MS pins are not routed).
+
+### SKR Pico (on-board TMC2209s)
+
+| Axis | Slot | STEP | DIR | EN | Endstop input | TMC2209 UART address |
+|---|---|---|---|---|---|---|
+| RA | X | GP11 | GP10 | GP12 | GP4 | 0 |
+| DEC | Y | GP6 | GP5 | GP7 | GP3 | 2 |
+| AZ | Z | GP19 | GP28 | GP2 | - | 1 |
+| ALT | E0 | GP14 | GP13 | GP15 | - | 3 |
+
+Note the address order X=0, **Y=2, Z=1**, E0=3 - set by the MS1/MS2 strapping
+on the SKR Pico PCB and the opposite of the JackW01 board.
+
+AZ and ALT are optional: set `AZ_DRIVER_TYPE`/`ALT_DRIVER_TYPE` to
+`DRIVER_TYPE_NONE` if your mount has no vertical axis motors.
+
+### JackW01 (TMC2209 modules)
+
+| Axis | Slot | STEP | DIR | EN | Endstop input | TMC2209 UART address |
+|---|---|---|---|---|---|---|
+| RA | X | GP7 | GP6 | GP5 | GP4 | 0 |
+| DEC | Y | GP11 | GP10 | GP5 | GP3 | 1 |
+| AZ | Z | GP13 | GP12 | GP5 | - | 2 |
+| ALT | E | GP15 | GP14 | GP5 | - | 3 |
+
+- **EN is shared**: all four enable lines are tied to GP5, so enable/disable
+  always affects every axis. Per-axis current control happens over UART
+  (IRUN/IHOLD) instead.
+- Use BTT TMC2209 modules with the PDN_UART pad bridge (the on-board resistor
+  linking RESET/TX and MS3/RX pads to PDN_UART). The carrier routes UART1
+  (GP8 TX, GP9 RX) to the driver sockets through R202/R201.
+
+## USB serial (control and flashing)
+
+- The USB port enumerates as a virtual COM port (USB CDC) and carries the
+  Meade/LX200 protocol used by OATControl, the ASCOM driver, and INDI. No
+  handshaking lines are required - hosts that open the port without asserting
+  DTR still receive replies.
+- Flashing: the board resets into BOOTSEL mode when a serial port opens at
+  1200 baud (the standard arduino-pico upload path), or hold BOOTSEL while
+  applying power.
+- `:XGM#` reports `RP2040` as the hardware type.
+
+## Info display (SSD1306 128x64 OLED, I2C)
+
+Config keys (set in your local config; the pins default correctly per board):
+
+```cpp
+#define INFO_DISPLAY_TYPE             INFO_DISPLAY_TYPE_I2C_SSD1306_128x64
+#define INFO_DISPLAY_I2C_ADDRESS      0x3C   // default
+#define INFO_DISPLAY_UPSIDE_DOWN      0      // 1 = rotate 180 degrees
+#define INFO_DISPLAY_MIRRORED         0      // 1 = flip horizontally
+```
+
+- **SKR Pico**: SDA = GP0, SCL = GP1 (I2C0) — the only header-accessible
+  I2C-capable GPIO pair on this board, and the firmware default when the
+  display is enabled. Wire SDA→IO0, SCL→IO1, VCC→5V, GND→GND, all on the
+  left-side header (bench-verified with a common 4-pin SSD1306 module on 5V).
+  **GP0/GP1 are shared with the default GPS wiring** — enable either the
+  display or GPS, not both (enforced at compile time).
+- **JackW01**: defaults are SDA = GP20, SCL = GP21 (free on that carrier);
+  override with `INFO_DISPLAY_I2C_SDA_PIN`/`..._SCL_PIN` to use other pins.
+
+> **Important (SKR Pico):** do **not** use GP20/GP21 for the display on the SKR
+> Pico. They only drive on-board MOSFETs (the HB/FAN/Laser power outputs,
+> labelled + and − on the board) and are never exposed as raw GPIO on any
+> connector. Wiring an I2C display to those pins hangs the bus and the
+> firmware (enforced at compile time).
+
+## GPS (SKR Pico)
+
+Wired to the left-side 5-pin header (IO0, IO1, GND, 5V) using UART0:
+
+| GPS module pin | Connect to | RP2040 GPIO |
+|---|---|---|
+| RX (module input) | IO0 | GP0 (MCU TX - fixed mux, TX only) |
+| TX (module output) | IO1 | GP1 (MCU RX - fixed mux, RX only) |
+| VCC | 5V | - |
+| GND | GND | - |
+
+Enable with `#define USE_GPS 1`. Tested with an ATGM336H-5N; any GPS module
+with a 3.3 V UART output works (the RP2040 GPIO are not 5 V tolerant).
+GP0/GP1 are shared with the info display's default pins on this board —
+enable either GPS or the display, not both (enforced at compile time).
+
+The JackW01 board has no default GPS wiring; leave `USE_GPS` at 0.
+
+## Hall homing sensors (RA and DEC)
+
+Active-LOW inputs on the endstop headers:
+
+| Axis | Input | GPIO | Config |
+|---|---|---|---|
+| RA | X-STOP | GP4 | `USE_HALL_SENSOR_RA_AUTOHOME`, `RA_HOMING_SENSOR_PIN`, `RA_HOMING_SENSOR_ACTIVE_STATE LOW` |
+| DEC | Y-STOP | GP3 | `USE_HALL_SENSOR_DEC_AUTOHOME`, `DEC_HOMING_SENSOR_PIN`, `DEC_HOMING_SENSOR_ACTIVE_STATE LOW` |
+
+The inputs are configured without pull-ups; open-drain Hall sensors need an
+external pull-up (10 kOhm to 3.3 V). The search distance defaults to 30 degrees
+(`RA_HOMING_SENSOR_SEARCH_DEGREES` etc. in `Configuration_adv.hpp`).
+
+## DEC endstops (SKR Pico)
+
+The two remaining endstop inputs can back up Hall homing with hardware limits:
+
+| Limit | Input | GPIO | Config key |
+|---|---|---|---|
+| DEC down | Z-STOP | GP25 | `DEC_ENDSWITCH_DOWN_SENSOR_PIN` |
+| DEC up | E-STOP | GP16 | `DEC_ENDSWITCH_UP_SENSOR_PIN` |
+
+Both are active LOW (`DEC_END_SWITCH_ACTIVE_STATE`). RA endstops have no
+default wiring on these boards - all four endstop inputs are allocated above.
+
+## Fan (SKR Pico)
+
+The FAN1 header is switched by a MOSFET on GP17 and carries the VIN rail
+(12/24 V). Set the power percentage in your config:
+
+```cpp
+#define RP2040_FAN1_POWER_PERCENT 60   // 0-100, default 100
+```
+
+## Not available by default on RP2040
+
+- **StallGuard driver autohome** - not implemented in the OAT firmware on any
+  platform; use Hall sensor homing instead (the DIAG outputs are unused)
+- **LCD menu display** - `DISPLAY_TYPE` must be `DISPLAY_TYPE_NONE`
+  (enforced at compile time)
+- **Gyro auto-leveling** - `USE_GYRO_LEVEL` must be 0
+- **Focuser stepper** - all four driver slots are used by RA/DEC/AZ/ALT
+- **Dew heater output** - no pin is wired on these boards
+- **WiFi/Bluetooth** - ESP32 builds only
+- SKR Pico's NeoPixel (GP24) and BLTouch (GP22/GP29) pins exist on the board
+  but are unused by the OAT firmware
+
+---
+
+Source of truth for any pin: the pins files linked at the top. If your wiring
+needs differ, every pin macro is `#ifndef`-guarded and can be overridden in
+your local configuration file.
diff --git a/matrix_build.py b/matrix_build.py
index dad16c54..56148c09 100644
--- a/matrix_build.py
+++ b/matrix_build.py
@@ -183,11 +183,25 @@ def update_dict(orig, patch):
     "rp2040_jackw01": update_dict(BUILD_FLAGS, {
         "USE_GPS": [0],
         "USE_GYRO_LEVEL": [0],
+        # No LCD menu display support on RP2040 (enforced by ConfigurationValidation)
         "DISPLAY_TYPE": [
             "DISPLAY_TYPE_NONE"
         ],
-        "INFO_DISPLAY_TYPE": [
-            "INFO_DISPLAY_TYPE_NONE"
+        # Both RP2040 boards carry on-board TMC2209s wired for UART only;
+        # A4988/standalone driver types need MS pins they do not route.
+        "RA_DRIVER_TYPE": [
+            "DRIVER_TYPE_TMC2209_UART"
+        ],
+        "DEC_DRIVER_TYPE": [
+            "DRIVER_TYPE_TMC2209_UART"
+        ],
+        "AZ_DRIVER_TYPE": [
+            "DRIVER_TYPE_NONE",
+            "DRIVER_TYPE_TMC2209_UART"
+        ],
+        "ALT_DRIVER_TYPE": [
+            "DRIVER_TYPE_NONE",
+            "DRIVER_TYPE_TMC2209_UART"
         ],
         "FOCUS_DRIVER_TYPE": [
             "DRIVER_TYPE_NONE"
@@ -197,13 +211,26 @@ def update_dict(orig, patch):
         ],
     }),
     "rp2040_skr_pico": update_dict(BUILD_FLAGS, {
-        "USE_GPS": [0],
         "USE_GYRO_LEVEL": [0],
+        # No LCD menu display support on RP2040 (enforced by ConfigurationValidation)
         "DISPLAY_TYPE": [
             "DISPLAY_TYPE_NONE"
         ],
-        "INFO_DISPLAY_TYPE": [
-            "INFO_DISPLAY_TYPE_NONE"
+        # Both RP2040 boards carry on-board TMC2209s wired for UART only;
+        # A4988/standalone driver types need MS pins they do not route.
+        "RA_DRIVER_TYPE": [
+            "DRIVER_TYPE_TMC2209_UART"
+        ],
+        "DEC_DRIVER_TYPE": [
+            "DRIVER_TYPE_TMC2209_UART"
+        ],
+        "AZ_DRIVER_TYPE": [
+            "DRIVER_TYPE_NONE",
+            "DRIVER_TYPE_TMC2209_UART"
+        ],
+        "ALT_DRIVER_TYPE": [
+            "DRIVER_TYPE_NONE",
+            "DRIVER_TYPE_TMC2209_UART"
         ],
         "FOCUS_DRIVER_TYPE": [
             "DRIVER_TYPE_NONE"
@@ -332,14 +359,23 @@ def set_ci_constraints(problem):
     problem.addConstraint(InSetConstraint({"DISPLAY_TYPE_NONE", "DISPLAY_TYPE_LCD_KEYPAD"}), ["DISPLAY_TYPE"])
     # problem.addConstraint(InSetConstraint({"DRIVER_TYPE_ULN2003"}), ["ALT_DRIVER_TYPE"])
 
-    # Restrict INFO_DISPLAY_TYPE_I2C_SSD1306_128x64 to mksgenlv21 and esp32 only
+    # Restrict INFO_DISPLAY_TYPE_I2C_SSD1306_128x64 to mksgenlv21, esp32 and rp2040_skr_pico only
     # (just to reduce compile times)
     def info_display_constraint(board, info_display):
         if info_display == "INFO_DISPLAY_TYPE_I2C_SSD1306_128x64":
-            return board in ["mksgenlv21", "esp32"]
+            return board in ["mksgenlv21", "esp32", "rp2040_skr_pico"]
         return True
     problem.addConstraint(info_display_constraint, ["BOARD", "INFO_DISPLAY_TYPE"])
 
+    # SKR Pico: the info display (defaults to GP0/GP1) and GPS share the only
+    # free header I2C/UART pair; ConfigurationValidation rejects the combo.
+    def skr_pico_gps_display_constraint(board, gps, info_display):
+        if board == "rp2040_skr_pico" and gps == 1 and info_display == "INFO_DISPLAY_TYPE_I2C_SSD1306_128x64":
+            return False
+        return True
+
+    problem.addConstraint(skr_pico_gps_display_constraint, ["BOARD", "USE_GPS", "INFO_DISPLAY_TYPE"])
+
 
 def print_solutions_matrix(solutions, short_strings=False):
     def get_value(vb, vk):
diff --git a/platformio.ini b/platformio.ini
index 7b68d651..fd850316 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -141,23 +141,19 @@ build_flags =
 
 [common_rp2xxx]
 extends = common_embedded
-; Use maxgerhardt platform wrapper to access Earle Philhower arduino-pico core.
-; The official platform-raspberrypi uses the Arduino-mbed core which has poorer
+; The 19200 default exists for the 8-bit AVR platforms; RP2040 USB CDC keeps up at 115200.
+monitor_speed = 115200
+; Use the maxgerhardt platform wrapper to access the Earle Philhower arduino-pico core.
+; The official platform-raspberrypi uses the Arduino-mbed core, which has poorer
 ; library compatibility and no flexible UART pin remapping.
 platform = https://github.com/maxgerhardt/platform-raspberrypi.git
 board_build.core = earlephilhower
-; SSD1306_128x64_Display.cpp includes SSD1306Wire.h unconditionally at the top of
-; the file (not guarded by INFO_DISPLAY_TYPE), so it can't compile without that
-; library. RP2040 boards don't support this display (ConfigurationValidation.hpp
-; forces INFO_DISPLAY_TYPE_NONE), so exclude the file instead of pulling in an
-; otherwise-unused, possibly RP2040-incompatible dependency.
-src_filter =
-	${common_embedded.src_filter}
-	-<SSD1306_128x64_Display.cpp>
 lib_deps =
+	mikalhart/TinyGPSPlus @ ^1.0.2
 	teemuatlut/TMCStepper @ ^0.7.1
 	waspinator/AccelStepper @ ^1.61
-	mikalhart/TinyGPSPlus @ ^1.0.2
+; SSD1306 info display support (SSD1306_128x64_Display.cpp is always compiled)
+	https://github.com/ClutchplateDude/esp8266-oled-ssd1306#4.6.2
 ; TimerInterrupt is AVR-only (uses OCR1A etc.); RP2040 uses hardware/timer.h directly
 lib_ignore = TimerInterrupt
 
@@ -166,7 +162,11 @@ extends = common_rp2xxx
 board = rpipico
 build_flags =
 	${env.build_flags}
-	-Wno-deprecated-declarations  ; arduino-pico core deprecates the B00000000-style Arduino::Binary.h macros used throughout the shared Mount code
+; arduino-pico core deprecates the B00000000-style Arduino::Binary.h macros used throughout the shared Mount code
+	-Wno-deprecated-declarations
+; The arduino-pico core headers and the SSD1306 OLED library trigger -Woverloaded-virtual
+; (-Werror) when parsed together in the same TU; the warning never fires in OAT code itself.
+	-Wno-overloaded-virtual
 	-D BOARD=BOARD_RP2040_JACKW01
 
 [env:rp2040_skr_pico]
@@ -174,7 +174,11 @@ extends = common_rp2xxx
 board = rpipico
 build_flags =
 	${env.build_flags}
-	-Wno-deprecated-declarations  ; arduino-pico core deprecates the B00000000-style Arduino::Binary.h macros used throughout the shared Mount code
+; arduino-pico core deprecates the B00000000-style Arduino::Binary.h macros used throughout the shared Mount code
+	-Wno-deprecated-declarations
+; The arduino-pico core headers and the SSD1306 OLED library trigger -Woverloaded-virtual
+; (-Werror) when parsed together in the same TU; the warning never fires in OAT code itself.
+	-Wno-overloaded-virtual
 	-D BOARD=BOARD_RP2040_SKR_PICO
 
 [env:native]
diff --git a/src/InfoDisplayRender.hpp b/src/InfoDisplayRender.hpp
index 3f9569bd..79287764 100644
--- a/src/InfoDisplayRender.hpp
+++ b/src/InfoDisplayRender.hpp
@@ -18,6 +18,10 @@ class InfoDisplayRender
     int _curLine;
 
   public:
+    // Draws the console-mode header (logo and product name).
+    // Overridden by subclasses; the default draws nothing.
+    virtual void drawHeader() {};
+
     InfoDisplayRender()
     {
         _consoleMode = true;
@@ -56,6 +60,12 @@ class InfoDisplayRender
         {
             drawContentFunction(this);
         }
+        else if (_consoleMode)
+        {
+            // Console-text updates arrive without a content callback; draw the
+            // header here so the boot console carries the logo on every frame.
+            drawHeader();
+        }
 
         if (_consoleMode)
         {
diff --git a/src/InterruptCallback.cpp b/src/InterruptCallback.cpp
index 18ab6601..9a28c206 100644
--- a/src/InterruptCallback.cpp
+++ b/src/InterruptCallback.cpp
@@ -22,8 +22,9 @@ PUSH_NO_WARNINGS
 POP_NO_WARNINGS
     #elif defined(ARDUINO_ARCH_RP2040)
         // Earle Philhower arduino-pico core exposes the Pico SDK alarm API.
-        // add_repeating_timer_us() fires a hardware alarm callback at a precise
-        // interval without relying on FreeRTOS or a second core.
+        // add_repeating_timer_us() fires a hardware-alarm callback at a precise interval in
+        // interrupt context, like the AVR timers. (The ESP32 port instead steps from a FreeRTOS
+        // task; this core has no RTOS at all, and no second core needs to be dedicated.)
         #include <hardware/timer.h>
     #else
         #error Unrecognized board selected. Either implement interrupt code or define the board here.
@@ -75,10 +76,10 @@ bool InterruptCallback::setInterval(float intervalMs, interrupt_callback_p callb
     _rp2040_callback = callback;
     _rp2040_payload  = payload;
 
-    // Positive delay_us means the period is measured from callback-start to
-    // callback-start (fixed wall-clock rate), which is what the stepper
-    // controller needs for consistent timing.
-    int32_t intervalUs = static_cast<int32_t>(intervalMs * 1000.0f);
+    // Negative delay_us gives a fixed wall-clock period from callback start to
+    // callback start (matching the AVR TimerInterrupt semantics). A positive
+    // delay would add the callback's own runtime to every period.
+    int64_t intervalUs = -static_cast<int64_t>(intervalMs * 1000.0f);
     return add_repeating_timer_us(intervalUs, rp2040_timer_isr, nullptr, &_rp2040_timer);
 }
 
@@ -90,8 +91,7 @@ void InterruptCallback::stop()
 void InterruptCallback::start()
 {
     // Re-arm with the same interval. The stored callback/payload are still set.
-    int32_t intervalUs = static_cast<int32_t>(_rp2040_timer.delay_us);
-    add_repeating_timer_us(intervalUs, rp2040_timer_isr, nullptr, &_rp2040_timer);
+    add_repeating_timer_us(_rp2040_timer.delay_us, rp2040_timer_isr, nullptr, &_rp2040_timer);
 }
 
     #endif
diff --git a/src/Mount.cpp b/src/Mount.cpp
index 67ac5b0a..db551328 100644
--- a/src/Mount.cpp
+++ b/src/Mount.cpp
@@ -498,9 +498,8 @@ void Mount::configureRAdriver(Stream *serial, float rsense, byte driveraddress,
     LOG(DEBUG_STEPPERS, "[MOUNT]: Requested RA motor rms_current: %d mA", rmscurrent);
     _driverRA->rms_current(rmscurrent, 1.0f);  //holdMultiplier = 1 to set ihold = irun
     _driverRA->pdn_disable(1);
-    _driverRA->ihold(31);
         #if defined(ARDUINO_ARCH_RP2040)
-    _driverRA->toff(4);  // toff(1) is too short for StealthChop to engage reliably on RP2040
+    _driverRA->toff(4);  // toff>=3 required for StealthChop slow-decay phase
         #else
     _driverRA->toff(1);
         #endif
@@ -543,7 +542,7 @@ void Mount::configureRAdriver(uint16_t RA_SW_RX, uint16_t RA_SW_TX, float rsense
     LOG(DEBUG_STEPPERS, "[MOUNT]: Requested RA motor rms_current: %d mA", rmscurrent);
     _driverRA->rms_current(rmscurrent, 1.0f);  //holdMultiplier = 1 to set ihold = irun
         #if defined(ARDUINO_ARCH_RP2040)
-    _driverRA->toff(4);  // toff(1) is too short for StealthChop to engage reliably on RP2040
+    _driverRA->toff(4);  // toff>=3 required for StealthChop slow-decay phase
         #else
     _driverRA->toff(1);
         #endif
@@ -591,11 +590,10 @@ void Mount::configureDECdriver(Stream *serial, float rsense, byte driveraddress,
     LOG(DEBUG_STEPPERS, "[MOUNT]: Requested DEC motor rms_current: %d mA", rmscurrent);
     _driverDEC->rms_current(rmscurrent, 1.0f);  //holdMultiplier = 1 to set ihold = irun
     _driverDEC->pdn_disable(1);
-    _driverDEC->ihold(31);
     _driverDEC->iholddelay(15);
     _driverDEC->TPOWERDOWN(255);
         #if defined(ARDUINO_ARCH_RP2040)
-    _driverDEC->toff(4);  // toff(1) is too short for StealthChop to engage reliably on RP2040
+    _driverDEC->toff(4);  // toff>=3 required for StealthChop slow-decay phase
         #else
     _driverDEC->toff(1);
         #endif
@@ -638,7 +636,7 @@ void Mount::configureDECdriver(uint16_t DEC_SW_RX, uint16_t DEC_SW_TX, float rse
     LOG(DEBUG_STEPPERS, "[MOUNT]: Requested DEC motor rms_current: %d mA", rmscurrent);
     _driverDEC->rms_current(rmscurrent, 1.0f);  //holdMultiplier = 1 to set ihold = irun
         #if defined(ARDUINO_ARCH_RP2040)
-    _driverDEC->toff(4);  // toff(1) is too short for StealthChop to engage reliably on RP2040
+    _driverDEC->toff(4);  // toff>=3 required for StealthChop slow-decay phase
         #else
     _driverDEC->toff(1);
         #endif
@@ -686,7 +684,7 @@ void Mount::configureAZdriver(Stream *serial, float rsense, byte driveraddress,
     LOG(DEBUG_STEPPERS, "[MOUNT]: Requested AZ motor rms_current: %d mA", rmscurrent);
     _driverAZ->rms_current(rmscurrent, AZ_MOTOR_HOLD_SETTING / 100.0);  //holdMultiplier = 1 to set ihold = irun
         #if defined(ARDUINO_ARCH_RP2040)
-    _driverAZ->toff(4);  // toff(1) is too short for StealthChop to engage reliably on RP2040
+    _driverAZ->toff(4);  // toff>=3 required for StealthChop slow-decay phase
         #else
     _driverAZ->toff(1);
         #endif
@@ -728,7 +726,7 @@ void Mount::configureAZdriver(uint16_t AZ_SW_RX, uint16_t AZ_SW_TX, float rsense
     LOG(DEBUG_STEPPERS, "[MOUNT]: Requested AZ motor rms_current: %d mA", rmscurrent);
     _driverAZ->rms_current(rmscurrent, AZ_MOTOR_HOLD_SETTING / 100.0);  //holdMultiplier = 1 to set ihold = irun
         #if defined(ARDUINO_ARCH_RP2040)
-    _driverAZ->toff(4);  // toff(1) is too short for StealthChop to engage reliably on RP2040
+    _driverAZ->toff(4);  // toff>=3 required for StealthChop slow-decay phase
         #else
     _driverAZ->toff(1);
         #endif
@@ -775,7 +773,7 @@ void Mount::configureALTdriver(Stream *serial, float rsense, byte driveraddress,
     LOG(DEBUG_STEPPERS, "[MOUNT]: Requested ALT motor rms_current: %d mA", rmscurrent);
     _driverALT->rms_current(rmscurrent, ALT_MOTOR_HOLD_SETTING / 100.0);  //holdMultiplier = 1 to set ihold = irun
         #if defined(ARDUINO_ARCH_RP2040)
-    _driverALT->toff(4);  // toff(1) is too short for StealthChop to engage reliably on RP2040
+    _driverALT->toff(4);  // toff>=3 required for StealthChop slow-decay phase
         #else
     _driverALT->toff(1);
         #endif
@@ -817,7 +815,7 @@ void Mount::configureALTdriver(uint16_t ALT_SW_RX, uint16_t ALT_SW_TX, float rse
     LOG(DEBUG_STEPPERS, "[MOUNT]: Requested ALT motor rms_current: %d mA", rmscurrent);
     _driverALT->rms_current(rmscurrent, ALT_MOTOR_HOLD_SETTING / 100.0);  //holdMultiplier = 1 to set ihold = irun
         #if defined(ARDUINO_ARCH_RP2040)
-    _driverALT->toff(4);  // toff(1) is too short for StealthChop to engage reliably on RP2040
+    _driverALT->toff(4);  // toff>=3 required for StealthChop slow-decay phase
         #else
     _driverALT->toff(1);
         #endif
@@ -866,7 +864,7 @@ void Mount::configureFocusDriver(Stream *serial, float rsense, byte driveraddres
     LOG(DEBUG_STEPPERS | DEBUG_FOCUS, "[FOCUS]: Requested Focus motor rms_current: %d mA", rmscurrent);
     _driverFocus->rms_current(rmscurrent, FOCUSER_MOTOR_HOLD_SETTING / 100.f);  //holdMultiplier = 1 to set ihold = irun
         #if defined(ARDUINO_ARCH_RP2040)
-    _driverFocus->toff(4);  // toff(1) is too short for StealthChop to engage reliably on RP2040
+    _driverFocus->toff(4);  // toff>=3 required for StealthChop slow-decay phase
         #else
     _driverFocus->toff(1);
         #endif
@@ -916,7 +914,7 @@ void Mount::configureFocusDriver(
     LOG(DEBUG_STEPPERS | DEBUG_FOCUS, "[FOCUS]: Requested Focus motor rms_current: %d mA", rmscurrent);
     _driverFocus->rms_current(rmscurrent, FOCUSER_MOTOR_HOLD_SETTING / 100.f);  //holdMultiplier = 1 to set ihold = irun
         #if defined(ARDUINO_ARCH_RP2040)
-    _driverFocus->toff(4);  // toff(1) is too short for StealthChop to engage reliably on RP2040
+    _driverFocus->toff(4);  // toff>=3 required for StealthChop slow-decay phase
         #else
     _driverFocus->toff(1);
         #endif
@@ -1169,6 +1167,8 @@ String Mount::getMountHardwareInfo()
     ret = F("ESP32,");
 #elif defined(__AVR_ATmega2560__)
     ret = F("Mega,");
+#elif defined(ARDUINO_ARCH_RP2040)
+    ret = F("RP2040,");
 #endif
 
     ret += F("NEMA|");
@@ -3405,7 +3405,11 @@ void Mount::updateInfoDisplay()
     // timeout, causing ASCOM errors.
     // We will update at 30Hz when idle, 5Hz when slewing one axis and skip updates when slewing both.
 
-    int refreshRateHz            = 30;
+    int refreshRateHz = 30;
+        #if defined(ARDUINO_ARCH_RP2040)
+    const bool isSlewingAny = (slewStatus() & (SLEWING_DEC | SLEWING_RA)) != 0;
+    refreshRateHz           = isSlewingAny ? 15 : 30;
+        #else
     const bool isSlewingRAandDEC = (slewStatus() & (SLEWING_DEC | SLEWING_RA)) == (SLEWING_DEC | SLEWING_RA);
     if (isSlewingRAandDEC)
     {
@@ -3415,7 +3419,7 @@ void Mount::updateInfoDisplay()
     {
         refreshRateHz = 5;  // Update the display slower
     }
-
+        #endif
     const long now = millis();
     if (now - _lastInfoUpdate > (1000 / refreshRateHz))
     {
@@ -3794,7 +3798,7 @@ void Mount::moveSteppersTo(float targetRASteps, float targetDECSteps, StepperAxi
     {
         if (_decUpperLimit != 0)
         {
-#if DEBUG_LEVEL > 0
+#if DEBUG_LEVEL != 0
             if (targetDECSteps > (float) _decUpperLimit)
             {
                 LOG(DEBUG_STEPPERS, "[STEPPERS]: MoveSteppersTo: DEC Upper Limit enforced. To: %l", _decUpperLimit);
@@ -3805,7 +3809,7 @@ void Mount::moveSteppersTo(float targetRASteps, float targetDECSteps, StepperAxi
 
         if (_decLowerLimit != 0)
         {
-#if DEBUG_LEVEL > 0
+#if DEBUG_LEVEL != 0
             if (targetDECSteps < (float) _decLowerLimit)
             {
                 LOG(DEBUG_STEPPERS, "[STEPPERS]: MoveSteppersTo: DEC Lower Limit enforced. To: %l", _decLowerLimit);
diff --git a/src/SSD1306_128x64_Display.cpp b/src/SSD1306_128x64_Display.cpp
index bae3c33b..945d87f7 100644
--- a/src/SSD1306_128x64_Display.cpp
+++ b/src/SSD1306_128x64_Display.cpp
@@ -55,25 +55,30 @@ void SDD1306OLED128x64::renderCallback(void *context)
     display->drawScreen();
 }
 
-void SDD1306OLED128x64::drawScreen()
+// Console-mode header, in the area 0,0 to 127,20.
+// Logo on the left, product name on the right.
+void SDD1306OLED128x64::drawHeader()
 {
     _display->setColor(WHITE);
-    if (_consoleMode)
-    {
-        // Draw header only in console mode, in the area 0,0 to 127,20
-        // Logo on the left. Base class renders console output text.
-        _display->setFont(OATLogo);
-        _display->drawString(0, 0, "!");
+    _display->setFont(OATLogo);
+    _display->drawString(0, 0, "!");
 
-        // Name on the right
-        _display->setFont(Bitmap5x7);
+    // Name on the right
+    _display->setFont(Bitmap5x7);
 #ifdef OAE
-        _display->drawString(32, 6, F("OpenAstroExplorer"));
+    _display->drawString(32, 6, F("OpenAstroExplorer"));
 #elif defined(OAM)
-        _display->drawString(32, 6, F("OpenAstroMount"));
+    _display->drawString(32, 6, F("OpenAstroMount"));
 #else
-        _display->drawString(32, 6, F("OpenAstroTracker"));
+    _display->drawString(32, 6, F("OpenAstroTracker"));
 #endif
+}
+
+void SDD1306OLED128x64::drawScreen()
+{
+    if (_consoleMode)
+    {
+        drawHeader();
     }
     else
     {
@@ -124,7 +129,11 @@ void SDD1306OLED128x64::drawIndicators(Mount *mount)
         _display->drawString(11, 59, F("L"));  // Memory chip icon
         _display->setFont(Bitmap3x5);
         long availMem = freeMemory();
-        if (availMem > 9999)
+        if (availMem > 999999)
+        {
+            _display->drawString(20, 59, String(availMem / 1024 / 1024, 1) + "M");
+        }
+        else if (availMem > 9999)
         {
             _display->drawString(20, 59, String(availMem / 1024) + "K");
         }
@@ -159,7 +168,11 @@ void SDD1306OLED128x64::drawIndicators(Mount *mount)
                 break;
             case 3:
                 {
-                    _display->drawString(55, 59, (String(F(" FW ")) + String(VERSION)).c_str());
+                    // Bitmap3x5 has no lowercase glyphs; uppercase so release-please's
+                    // "v" version prefix renders as V instead of an out-of-range glyph.
+                    String fw = String(F(" FW ")) + String(VERSION);
+                    fw.toUpperCase();
+                    _display->drawString(55, 59, fw.c_str());
                 }
                 break;
             case 4:
diff --git a/src/SSD1306_128x64_Display.hpp b/src/SSD1306_128x64_Display.hpp
index 32f14633..6e59daf6 100644
--- a/src/SSD1306_128x64_Display.hpp
+++ b/src/SSD1306_128x64_Display.hpp
@@ -1,6 +1,20 @@
 #pragma once
+// In PlatformIO builds the real pragma wrappers come from macros/gcc/Macros.hpp,
+// which is force-included via the -include build flag. Arduino IDE builds have no
+// such flag, and this header can be the first to use the macros (SSD1306_128x64_Display.cpp
+// includes it directly), so provide the same no-op fallbacks as inc/Globals.hpp.
+#if !defined(PUSH_NO_WARNINGS)
+    #define PUSH_NO_WARNINGS ;
+#endif
+#if !defined(POP_NO_WARNINGS)
+    #define POP_NO_WARNINGS ;
+#endif
+// The arduino-pico core headers (the Arduino.h chain) and the OLED library are not
+// warning-clean under our strict flag set (-Wshadow).
+PUSH_NO_WARNINGS
 #include <Arduino.h>
 #include "SSD1306Wire.h"
+POP_NO_WARNINGS
 #include "Configuration.hpp"
 #include "Utility.hpp"
 #include "Version.h"
@@ -55,6 +69,9 @@ class SDD1306OLED128x64 : public InfoDisplayRender
     void static renderCallback(void *context);
     void drawScreen();
 
+    // Console-mode header: logo and product name
+    void drawHeader();
+
     // Build the display from the mount
     void renderScreen(void *mount);
 
diff --git a/src/Utility.cpp b/src/Utility.cpp
index 7937dda4..16248a1d 100644
--- a/src/Utility.cpp
+++ b/src/Utility.cpp
@@ -3,11 +3,11 @@
 #include "../Configuration.hpp"
 #include "Utility.hpp"
 
-#if DEBUG_LEVEL > 0
+#if DEBUG_LEVEL != 0
     #include <stdarg.h>
 #endif
 
-#if DEBUG_LEVEL > 0
+#if DEBUG_LEVEL != 0
 unsigned long RealTime::_pausedTime   = 0;
 unsigned long RealTime::_suspendStart = 0;
 int RealTime::_suspended              = 0;
@@ -293,7 +293,7 @@ int freeMemory()
 }
 #endif
 
-#if DEBUG_LEVEL > 0
+#if DEBUG_LEVEL != 0
 
 String formatArg(const char *input, va_list args)
 {
@@ -410,15 +410,26 @@ void logv(int levelFlags, String input, ...)
     #if BUFFER_LOGS == true
         addToLogBuffer(formatArg(input.c_str(), argp));
     #else
-        DEBUG_SERIAL_PORT.print("[");
-        DEBUG_SERIAL_PORT.print(String(now));
-        DEBUG_SERIAL_PORT.print("]{");
-        DEBUG_SERIAL_PORT.print(String(delta));
-        DEBUG_SERIAL_PORT.print("}ms:");
-        DEBUG_SERIAL_PORT.print(String(freeMemory()));
-        DEBUG_SERIAL_PORT.print("B: ");
-        DEBUG_SERIAL_PORT.println(formatArg(input.c_str(), argp));
+        // Compose the whole line and write it with a single print() call.
+        // The arduino-pico USB CDC write path can wedge when many small
+        // writes per line race the TinyUSB FIFO (each write re-enters the
+        // USB mutex); one write per line minimizes the exposure.
+        String line = "[";
+        line += String(now);
+        line += "]{";
+        line += String(delta);
+        line += "}ms:";
+        line += String(freeMemory());
+        line += "B: ";
+        line += formatArg(input.c_str(), argp);
+        line += "\n";
+        DEBUG_SERIAL_PORT.print(line);
+        #if !defined(ARDUINO_ARCH_RP2040)
+        // UART outputs drain from a ring buffer; flush so the tail of the log is not
+        // lost if the firmware crashes right after logging (matters for AVR debugging).
+        // On RP2040 the port is USB CDC, where flush() can stall without a reader.
         DEBUG_SERIAL_PORT.flush();
+        #endif
     #endif
         lastLog = now;
         va_end(argp);
diff --git a/src/Utility.hpp b/src/Utility.hpp
index d8801ebd..91847c6c 100644
--- a/src/Utility.hpp
+++ b/src/Utility.hpp
@@ -10,7 +10,7 @@
 String getLogBuffer();
 int freeMemory();
 
-#if DEBUG_LEVEL > 0
+#if DEBUG_LEVEL != 0
     #define LOG(level, format, ...) logv((level), (F(format)), ##__VA_ARGS__)
 
 // Realtime timer class using microseconds to time stuff
diff --git a/src/b_setup.hpp b/src/b_setup.hpp
index 2b2c21c0..ac45478c 100644
--- a/src/b_setup.hpp
+++ b/src/b_setup.hpp
@@ -130,22 +130,27 @@ void setup()
     // OATControl (and other apps using C# SerialPort) open the port with DTR=false.
     // The Philhower USB CDC SerialUSB::write() gates TX on tud_cdc_connected() which
     // requires DTR=true, so all responses are silently dropped for those hosts.
-    // ignoreFlowControl(true) bypasses the DTR check and always sends TX data.
+    // ignoreFlowControl(true) bypasses the DTR check so replies always flow.
+    // Bounded by the core: with no (or a non-DTR) host, writes stop as soon as the
+    // ~257-byte CDC TX FIFO is full (tud_cdc_connected() false breaks the write
+    // loop immediately); a connected host that stops draining is dropped after
+    // 1 second without progress. Headless boots never stall on logging.
     Serial.ignoreFlowControl(true);
     #endif
-    #if DEBUG_LEVEL > 0 && DEBUG_SEPARATE_SERIAL == 1
+    #if DEBUG_LEVEL != 0 && DEBUG_SEPARATE_SERIAL == 1
     DEBUG_SERIAL_PORT.begin(DEBUG_SERIAL_BAUDRATE);
     #endif
-    // RP2040 USB CDC: wait up to 3 s for the host to open the port so that
-    // LOG() calls below are not dropped (or do not block indefinitely).
-    // This only matters when DEBUG_LEVEL > 0 — in release builds LOG() is
-    // a no-op, so the wait is compiled out.
-    #if defined(ARDUINO_ARCH_RP2040) && DEBUG_LEVEL > 0
-    {
-        uint32_t _cdcWaitStart = millis();
-        while (!Serial && (millis() - _cdcWaitStart) < 3000UL)
-        { /* spin */
-        }
+    // RP2040 USB CDC: give a console up to 3 seconds to attach so the boot
+    // log stays visible. Bounded, never infinite: a mount powered externally
+    // in the field must boot with no USB host attached. With no host attached
+    // the CDC TX FIFO holds only ~250 bytes and further writes are dropped, so
+    // a headless debug build simply boots invisibly (reset with the console
+    // open to see the full log). Release builds (DEBUG_LEVEL == 0) skip this
+    // entirely.
+    #if defined(ARDUINO_ARCH_RP2040) && DEBUG_LEVEL != 0
+    uint32_t consoleWaitStart = millis();
+    while (!Serial && (millis() - consoleWaitStart < 3000UL))
+    { /* spin until the console connects or the timeout expires */
     }
     #endif
 #endif
@@ -218,9 +223,6 @@ void setup()
     /////////////////////////////////
     //   RP2040: UART pin remapping
     /////////////////////////////////
-    // The Philhower arduino-pico core requires setTX()/setRX() to be called
-    // before begin() to remap UART pins away from their defaults. This must
-    // happen before any Serial2.begin() calls in the driver setup below.
     // RP2040_UART1_TX_PIN / RP2040_UART1_RX_PIN are defined in the board's
     // pins file only for RP2040 targets that use a non-default UART1 mapping.
 #if defined(ARDUINO_ARCH_RP2040) && defined(RP2040_UART1_TX_PIN) && defined(RP2040_UART1_RX_PIN)
@@ -256,10 +258,10 @@ void setup()
     #endif
 
     #ifdef RA_SERIAL_PORT
-        #if defined(ARDUINO_ARCH_RP2040)
-    RA_SERIAL_PORT.begin(115200);  // TMCStepper requires 115200 baud on the Philhower RP2040 core
-        #elif defined(OAE)
+        #ifdef OAE
     RA_SERIAL_PORT.begin(57600, SERIAL_8N1, RA_RX_PIN, RA_TX_PIN);
+        #elif defined(ARDUINO_ARCH_RP2040)
+    RA_SERIAL_PORT.begin(115200);  // TMCStepper requires 115200 baud on RP2040
         #else
     RA_SERIAL_PORT.begin(57600);  // Start HardwareSerial comms with driver
         #endif
@@ -291,10 +293,10 @@ void setup()
     pinMode(DEC_DIAG_PIN, INPUT);
     #endif
     #ifdef DEC_SERIAL_PORT
-        #if defined(ARDUINO_ARCH_RP2040)
-    DEC_SERIAL_PORT.begin(115200);  // TMCStepper requires 115200 baud on the Philhower RP2040 core
-        #elif defined(OAE)
+        #ifdef OAE
     DEC_SERIAL_PORT.begin(57600, SERIAL_8N1, DEC_RX_PIN, DEC_TX_PIN);
+        #elif defined(ARDUINO_ARCH_RP2040)
+    DEC_SERIAL_PORT.begin(115200);  // TMCStepper requires 115200 baud on RP2040
         #else
     DEC_SERIAL_PORT.begin(57600);  // Start HardwareSerial comms with driver
         #endif
@@ -315,7 +317,7 @@ void setup()
         #endif
         #ifdef AZ_SERIAL_PORT
             #if defined(ARDUINO_ARCH_RP2040)
-    AZ_SERIAL_PORT.begin(115200);  // TMCStepper requires 115200 baud on the Philhower RP2040 core
+    AZ_SERIAL_PORT.begin(115200);  // TMCStepper requires 115200 baud on RP2040
             #else
     AZ_SERIAL_PORT.begin(57600);  // Start HardwareSerial comms with driver
             #endif
@@ -336,7 +338,7 @@ void setup()
         #endif
         #ifdef ALT_SERIAL_PORT
             #if defined(ARDUINO_ARCH_RP2040)
-    ALT_SERIAL_PORT.begin(115200);  // TMCStepper requires 115200 baud on the Philhower RP2040 core
+    ALT_SERIAL_PORT.begin(115200);  // TMCStepper requires 115200 baud on RP2040
             #else
     ALT_SERIAL_PORT.begin(57600);  // Start HardwareSerial comms with driver
             #endif
@@ -355,7 +357,7 @@ void setup()
         #ifdef FOCUS_SERIAL_PORT
     LOG(DEBUG_FOCUS, "[FOCUS]: setup(): focus TMC2209U starting comms");
             #if defined(ARDUINO_ARCH_RP2040)
-    FOCUS_SERIAL_PORT.begin(115200);  // TMCStepper requires 115200 baud on the Philhower RP2040 core
+    FOCUS_SERIAL_PORT.begin(115200);  // TMCStepper requires 115200 baud on RP2040
             #else
     FOCUS_SERIAL_PORT.begin(57600);  // Start HardwareSerial comms with driver
             #endif
@@ -653,8 +655,9 @@ void setup()
 
 #else
     #ifndef NEW_STEPPER_LIB
-    // 2 kHz updates (higher frequency interferes with serial communications and complete messes up OATControl communications)
-    if (!InterruptCallback::setInterval(0.5f, stepperControlTimerCallback, &mount))
+    // Stepper servicing rate: 2 kHz on AVR (higher rates there interfere with serial
+    // communications and mess up OATControl), 5 kHz on RP2040 (see STEPPER_CONTROL_INTERVAL_MS).
+    if (!InterruptCallback::setInterval(STEPPER_CONTROL_INTERVAL_MS, stepperControlTimerCallback, &mount))
     {
         LOG(DEBUG_MOUNT, "[SYSTEM]: CANNOT setup interrupt timer!");
     }
diff --git a/src/f_serial.hpp b/src/f_serial.hpp
index 7f8458a1..64d5644b 100644
--- a/src/f_serial.hpp
+++ b/src/f_serial.hpp
@@ -19,7 +19,7 @@ void serialLoop()
     mount.loop();
     mount.displayStepperPositionThrottled();
 
-    #ifdef ESP32
+    #if defined(ESP32)
     processSerialData();
     #endif
 
diff --git a/src/testmenu.cpp b/src/testmenu.cpp
index 2649ea7d..f13e7571 100644
--- a/src/testmenu.cpp
+++ b/src/testmenu.cpp
@@ -479,7 +479,7 @@ void TestMenu::onKeyPressed(int key)
                     Serial.println(F("Mount reset, EEPROM erased."));
                     _currentMenu->display();
                 }
-                else if (action = F("PassthroughCmd"))
+                else if (action == F("PassthroughCmd"))
                 {
                     Serial.print(F("Enter LX200-OAT command to send to mount: "));
                     TestMenu::setMenuState(testMenuState_t::WAITING_ON_COMMAND);