We already have quite a lot of devices, and now we need to update the firmware from RUI_3.5.1 to RUI_3.5.6. The devices have access to UART-2. But due to the fact that these devices are located in an inaccessible place, it is not convenient to access them from a PC with the standard “RAK Serial Port Tool” program. There is an idea to make a hardware bootloader for the STM32, the flash of which will contain a binary file for transferring it to the RAK3172-E.
Actually, the loading algorithm itself is of interest.
- Apply power
- Run the command “AT+BOOT”
Now I don’t understand in what form and when to transfer the binary file via UART-2.