Feature Request: Try 1MBaud if 115k does not lead to communication

[uhi22]

This was discussed here:
https://openinverter.org/forum/viewtopic.php?p=62575#p62575

Precondition: STM32 and ESP32 negotiated the 1MBaud and are talking to each other.
Action: ESP32 makes a watchdog reset (for whatever reason. The reason does not matter.)
Observed behavior: The ESP32 shows no data in the web interface, because the STM32 sends with 1MBaud, but the ESP32 listens with 115k.
Expected behavior: The ESP32 shall listen with 1MBaud, if it does not see senseful communication with 115k.

Prio: Low (nice to have)

[jsphuebner]

This has been addressed in 869b5de
At the first command after boot up the fastuart command is sent to the STM32 but the result is ignored. So either the STM32 is already in 1M mode or is switched to 1M mode. The ESP communicates at 1M either way.
This breaks backward compatibility with firmware that doesn't support 1M baud rate but this feature was added many years ago.

If the STM32 resets this commit does not help. The STM32 will never be switched to 1M mode after reset