Does the m1/m2 expose a serial port on the USB-C connector? I haven't seen that outside of mobile phones that require special debugging jigs (most requiring a secret resistor values between various pins to turn it on).
This actually looks like something I needed to build for some low-level bootloader work, and I had exactly the same sort of poor failure rate for my USB switches. I chalked it up to my inexperience in board design at the time, but I guess the board production house might have just been pretty poor.
More info in the README: https://git.kernel.org/pub/scm/linux/kernel/git/maz/cs-hw.gi...
This actually looks like something I needed to build for some low-level bootloader work, and I had exactly the same sort of poor failure rate for my USB switches. I chalked it up to my inexperience in board design at the time, but I guess the board production house might have just been pretty poor.
EDIT: I used a TS3USB30ERSWR in my design.