There are 3 ways to Flashing MCU firmware:

Method 1. Flashing with PC.

the v2.8 2021/3 and later version has bootloader,so we can flash it from PC.

1. Connect up your printer to your PC via the microUSB port. Make sure the external Power(12/24V) is on, and jumpers on as showing in bellow picture,also disconnect the uart LCD if have connected uart LCD.

2. Start the "FlashTool_STM32.exe", make sure you are on the right com port to double-check just unplug your printer and click refresh, the right one will be displayed at the window.

3. Select the "firmware.bin" and it will ask you to reset your printer,do this by connect the Reset(RST) pin to GND for 1 second and then disconnect,if there is no response please connect and disconnect again.

Method 2. Flashing with RaspberryPi from webpage.

the v2.8 2021/3 and later version has bootloader,so we can flash it from the RaspberryPi.

1) configure the hardware with jumpers and line,the yellow line is used for connectin the reset pin of MCU to PI,so PI can restart the MCU before flashing.

2) click the button(Run Pandapi mode/Run Klipper mode) on the webpage.

Method 3. Flashing with stlink tools.

1). Connect stlinkV2 to board.

2). Install flash tool STM32 ST-LINK Utility

3). Download MCU firmware: MCU hex file.

4). Connect STLinkV2 to PC,Start to flash.