MarlinFW build issue GD32F30RET6 Creality V4.2.2 board using MFL

[ptorok74]

Hi,

I got an old Ender 5 Pro, pretty decent piece, love to tinker it. It has a Creality V4.2.2 silent board with a GD32F303RET6 chip. Checked, twice. :)
It should be better then the STM32F103, so I decided to push a new FW on it. Go with 2.1.3-b3 or latest 2.1.x bugfix release.

Very basic config deviating from default:
config.h
#define MOTHERBOARD BOARD_CREALITY_V422_GD32_MFL
#define SERIAL_PORT 0
#define BAUDRATE 115200
#define FAN_SOFT_PWM

platformio.ini
[platformio] default_envs = GD32F303RE_creality_mfl
[env] monitor_speed = 115200

features.ini
HAS_MARLINUI_U8GLIB = U8glib-HAL=https://github.com/MarlinFirmware/U8glib-HAL/archive/refs/heads/master.zip

Successful build (no warnings!!!) / no boot / no screen.

Looking into the firmware.bin file, there is a strange section, It seems the MFL/*.cpp error is compiled INTO the firmware. Makes no sense for me:
------firmware.bin-------
Selected pin is not a valid pin number ERROR: Invalid timer instance! Invalid TIMER instance!
C:\Users\peter.platformio\packages\framework-arduino-mfl\system\MFL\MFL\Source\GPIO/GPIO.cpp
C:\Users\peter.platformio\packages\framework-arduino-mfl\system\MFL\MFL\Source\DMA/DMA.cpp
C:\Users\peter.platformio\packages\framework-arduino-mfl\system\MFL\MFL\Source\ADC/ADC.cpp
C:\Users\peter.platformio\packages\framework-arduino-mfl\system\MFL\MFL\Source\TIMER/TIMER.cpp
C:\Users\peter.platformio\packages\framework-arduino-mfl\system\MFL\MFL\Source\USART/USART.cpp
Invalid port/pin Invalid output speed ERROR: Invalid usart instance!
Invalid USART instance! DMA_TX and DMA_DUAL modes are not supported %%%d.%df
Printer halted. kill() called! !! KILL caused by too much inactive time - current command: PowerUp
External Reset
Brown out Reset
Watchdog Reset
Software Reset
Marlin bugfix-2.1.x
Last Updated: 2025-11-02 | Author: (none, default config)
Compiled: Nov 2 2025
--------firmware.bin --------

At this point, I'm kinda lost... any idea what am I missing?

GD32F303RE_creality_mfl.zip

Peter

ps.: I have a MarlinFW 2.1.3-b2 prebuilt FW working, I assume built using STM32F103RE emulated architecture. very basic features though.