Trigorilla Pro mainboard

• 32bit Cortex-M3 MCU (STM32F103ZET6)
• Soldered A4988 stepper drivers
• WIFI slot layout matches ESP-01 layout
• Manufactured by cbd-3d?
• PL2303 USB to Serial (max baudrate seems to be 230400)
• 

Pinout

• Datasheet (Page 27)
• PB0: Beeper
• PD3: LED
• PG4: Capacitor? (Power LED turns off slowly if pin is set HIGH)
• PA9: Serial USB Communication?

Flashing bootloader

• Install Arduino STM32
• Remove JP1 jumper and set SW1 jumper to USB mode
• Use stm32flash tool located in Arduino_STM32/tools/..../stm32flash
• ./stm32flash -b 230400 -w generic_boot20_pd3.bin -v -g 0x0 <port>

Stepper driver replacement

• Trinamic Replacement Notes for replacing A4988 with TMC2208
• Soldering Video
• Replace C45 capacitor (100nF) with 0603 22nF 50V
• Replace R46 and R47 resistors (68mOhm) with 0603 150mOhm 0,5W

Sources

• ChiTu mainboard manual
• Thingiverse hardware thread