USB (and other) issues on Pi Zero 2w

[zaicik]

USB port on my Pi Zero 2W is not working properly.

Here's a list of symptoms I compiled and things I've tried:

1/ plugged in various USB drives directly
=> they don't show up in fpp (i.e. in FPP Backup, even after clicking refresh)
=> they don't show up in the os (lsusb -t returns a single line: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=dwc2/1p, 480M)

1b/ plugged in various USB drives through a USB hub, and plugged in an sd card reader => same results

2/ plugged in various USB audio interfaces
=> they don't show up in FPP (Settings/Audio-Video only list "Dummy") (lsusb -t returns the same result, and aplay -l returns: card 0: Dummy [Dummy], device 0: Dummy PCM [Dummy PCM]) *more on that later

3/ plugged an usb-usb cable to link-up with a Pico or a NodeMCU
=> no luck either (ttyACM0 doesn't magically appear)

4/ USB Tethering doesn't work (tested with a macbook, an iPad and a PC)


FURTHER INFORMATION:
All this is on FPP v7.5.
I tried with 2 different Pi Zero 2W, with and without a HAT attached.
The USB port has no physical issues (all those things above work perfectly well with a Raspbian sd-card inserted)

Out of curiosity and seeking to trace the source of the issue, I tried older builds and found out that USB tethering works on my Zero 2Ws with FPP v5.5 and doesn't with v6.3 (i didn't try all intermediates, but I'm guessing the jump to 6.0 is when it happened)


ONE LAST THING (cf my * early, and then I'm done for today):
with v7.5: "Dummy" is the only audio output device available (on a bare install, no HAT, no strings configured)
with v5.5: two devices were available (forgot the names but one was for audio over hdmi)

Guidance into solving these issues would be greatly appreciated <3

[zaicik]

Quick update:

Digging further, I noticed that the USB driver on my Rasbian was the dwc_otg, while the FPP one was dwc2

A little bit of Googling and fumbling later (actually a medium-sized bit... I'm fairly new to this): 

• I edited /boot/config.txt
• Looked for the line dtoverlay=dwc2 
• Replaced it with dtoverlay=dwc_otg

=> USB devices (sound, mass storage) are now detected when plugged in and work correctly
=> Doesn't seem to have introduced any adverse side effects... for me (please note I'm just starting and at this point I have a very simple configuration with no DMX, Midi, etc.)


Also, not a problem for me, but please note that it didn't solve the USB tethering issue.