Hi, I am using a RAK3172 module on a custom PCB and am having an issue with the latest firmware release for this module.
The RAK module was working perfectly when using the old 1.0.4 firmware, however I wanted to use some commands from the RUI3 protocol.
Now seemingly randomly the device enters a mode where it sends <.BOOT MODE> over UART2 on powerup. When in this mode, the module is completely unresponsive. This occurs when the Boot0 pin is floating or when it is grounded. I can also force entry into this mode by sending the AT+BOOT command while the module is still being responsive.
Here’s an example of what is being sent from the device:
The module will stay in this mode even during reset or powering on/off
While in this “boot mode” STM32CubeProgrammer cannot communicate with the module:
The only way I have found to exit this mode is to tie the Boot0 pin to 3V3. When doing this, the device stops sending <.BOOT MODE>, and can connect to the programmer:
From here I have to flash a new version of the firmware from the file RAK3172-E_latest_final.hex using the programmer connected over UART. Once I do this the module returns to a usable state for a small amount of time, but then eventually returns to <.BOOT MODE>.
Is this a bug with the firmware, or an error in my processes?