#Mini fabrikator v2 pcb
This printer is also know as Malyan M100 This is board schematics from printer I have at home.
You can read more about it at this link: http://www.lemilica.com/reversing-mini-fabrikator-v2-malyan-m100-3d-printer/
On bluepill I have tested connection to ESP8266 and all is working. All sensors when not connected shows about 100 degrees, that is probably OK. I have connected SD card to it, and with original bootloader I can flash some code on bluepill. I can send GCODE to SD card.
I can now compile Marlin firmware for M200
I did solve serial issue and working serial branch is now here
https://github.com/marvin-sinister/Marlin/tree/radiona-2.0.x
I did not try this code on priter, so be carefull ...
One problem still remains, fox Z axis M100 uses ULN2003 so fot Z you need write some step direction function.
If you realy think you need bootloader, you can contact me over email