Thanks for replying.
I'm using the latest from here https://www.armbian.com/orange-pi-zero/ marked as legacy stable. Not sure what kernel it's using.
I tried `modprobe -r g_serial` and got: `modprobe: FATAL: Module g_serial is in use.` I tried with the otg port plugged in and unplugged.
`modprobe g_hid` returned `modprobe: ERROR: could not insert 'g_hid': No such device`