The MPMini/Malyan M200 V1, V2, and Pro (V3, for all purposes) run on an STM32Fxxyy processor using a firmware which is claimed to not be derived from Marlin (hook a serial monitor to the display port and make your own decisions whether or not that's true). These project logs follow my progress making Marlin 2.x run on this board across multiple hardware revisions/Arduino cores.
V1 and V2 work today if built with the Arduino IDE. V3 in theory works (it's the same processor as most V2s) though ABL doesn't work without EEPROM emulation. M300 support would most likely be a different project, but it feels like an extension of this one, so for now, I'm leaving it here.