Added ELF downloads for debugging tasmota firmware on exception crashes

[rai68]

made it so you can download 'FIRMWARE.ELF'

Let me know if there is anything ive messed up

[benzino77]

Thanks!
Could you please tell me why we need to add this functionality? I have to admit that I have no clue what for those ELF files would be needed.

[rai68]

They're used by espExceptionDecoder to decode the stack trace of a hardware crash.

The program normally uses .elf files created by Arduino complier. But since here we are using Platform.io ESP exception decoder asks for an ELF file since the Tasmota firmware isn't complied on the same Arduino instance.

And the .elf file is created with the firmware and when trying to decode an exception it requires the specific .elf file created with the firmware. Using TasmoCompiler it can be hard to extract the .elf file if you get a exception crash.

So I added the functionally to be able to download it.

[benzino77]

I'm not sure that "average" Tasmota user will need to debug stack trace of their devices.I'm sure it is a nice feature to have it available, but I don't want to confuse users with "firmware.elf" button next to the "firmware.bin/firmware.bin.gz" button. Maybe a switch (somewhere in the menu/top AppBar) to turn on "Advanced mode" which will be disabled by default?
After choosing AM, one could reach additional GUI features like download ELF file.