Incorrect monitoring in 26MHz targets

[SergioGasquez]

After merging esp-rs/esp-hal#1165, I've regenerated C2 stub, with dprint feature enabled, stub is attached. Using this stub, I can flash both a 26MHz C2 and a 40MHz C2, but there are still a few issues:

• I can't properly monitor a 26MHz C2 (baudrate is not correct, hence I only see noise)
  • Tested using different baudrates in espflash (115_200)
  • Also tried using screen, same result.
• espflash reports 26MHz C2 as 40MHz
  • We use a UART reg to estimate the freq.

If I use a C stub, I cant flash a 26MHz C2 as espflash does not detect the OHAI message, which results in a timeout, this probably happens because we are using an incorrect baudrate and we cant decode the message.

Using --no-stub, everything works fine.

This is the branch where I am conducting the tests: https://github.com/SergioGasquez/espflash/tree/fix/flash-26mhz

stub_flasher_32c2.zip

Update: I've been debugging this morning with @bjoernQ and we found the part of issue, we were using APB clock as source for UART, we changed it, regenerated the stub, and now espflash detects the xtal frequency properly. Here is the updated stub:

stub_flasher_32c2.zip