Update ELRS firmware

[benedikt-bartscher]

Hey @mikeneiderhauser, thanks you for your awesome work! Is there a way to update the ELRS receiver firmware? Or is it currenty always in USB HID mode?

[mikeneiderhauser]

If tried a few ways to get over usb flashing to work with ELRS configurator but have ran into numerous issues in the process. In order to update the firmware on the ELRS Receiver. It is recommended to flash it over WiFi.

The pi pico itself given current firmware is always in HID mode.

[benedikt-bartscher]

Thanks for your answer. Sadly some ELRS receivers don't have wifi (868mhz ones).
Couldn't we just introduce a boot delay in which the user can press for example a button to start in FW update mode?
Betaflight allows updating elrs receivers with serial passtrough, i used it many times, works great. Did you try this https://docs.arduino.cc/built-in-examples/communication/SerialPassthrough ?

[mikeneiderhauser]

You can't do just native serial pass through (at least on the ESP based RX's, haven't tried the STM based RX's) as the boot loader does dynamic baud rates for programming. I've tried dedicated bridge / serial pass through firmware that is supposed to do dynamic baud without success.

[countofkrakow]

Just submitted a PR for this

[mikeneiderhauser]

^ ill be taking a look at this PR hopefully this weekend time permitting

[mikeneiderhauser]

PR merged, elrs passthrough flashing is now functional