Marlin on Blackpill

Want to do your own 3D printer controller?
I did one with bluepill stm32F103 but the memory was used to 98% so no space for fancy features.....
Now you can find the blackpill with stm32F401 from weact (https://github.com/WeActTC/MiniSTM32F4x1) on aliexpress....

How to compile Marlin-bugfix-2.0.x (2.0.8) downloaded 02_2021 on stm32F401ce blackpill using Platformio in VisualStudioCode:

Add blackpill_f401ce.json from https://github.com/platformio/platform-ststm32/blob/develop/boards/blackpill_f401ce.json
in ../Marlin-2.0.x/buildroot/share/PlatformIO/boards/.

in ../Marlin/src/pins/stm32f4
Create a file "pins_blackpill_f401ce.h" containing the description of the board.
add #define FLASH_EEPROM_EMULATION //emulate a EEPROM 4Kb in flash

In Marlin/src/pins/pins.h
in section
//
// STM32 ARM Cortex-M4F
//
add
'#elif MB(blackpill_f401ce)
'#include "stm32f4/pins_blackpill_f401ce.h" // STM32F4/pins_blackpill_f401ce.h

in ../Marlin-2.0.x/Marlin/src/core/boards.h
in