Solved I2C bitrate crash and clockstreching.
Hi Pete (user67316),
these two files contain Frida's changes:
The current code operates at a little over 300khz, which is quite close to the 400khz max of many devices. It was significantly optimized from the espressif code and all the inner loops were pretty much rewritten. IIRC I tried to make it as fast as I could without exceeding 400khz and still leaving some dials in there to easily turn the speed down to 100khz.
I AM able to speed test and compare - see my other query - once I'm sure which code to grab I'll try it and report speed back - it is quite easy to speed up the ESPRESSIF code but this of course has additional checks for clock stretching.