Crashed my mobula6 hdzero (for the 200th time), but this time I can't troubleshoot the problem. My OSD disappeared and the drone will not arm. Drone appears to and sounds as though it's starting up right, but then no osd and can't arm. Video works fine so the vtx, cam, etc are all receiving power and working. Motors play their start up tune(pacman )
Any ideas on troubleshooting steps, or is this just a replace the FC and that's that situation?
Thanks!

It sounds like the flight controller portion of your AIO is having issues. Have you tried connecting it to a computer and seeing what Betaflight Configurator shows for arming disable flags?

Check the soldering of all wires from the video to the flight controller. If the quad is arming, but there is no video, then most likely the soldering of the wires is broken.
I was teaching kids how to fly for the first time and my drone got hit quite a bit on the floor and ceiling. The video has disappeared. Otherwise everything was fine. The ground wire came loose.

No OSD - but video = camera and vtx getting power.. but FC problem.

BLHeli chime = first part means BBM chip BLHeli code running. 2nd part (beep-bop) means communication to FC is OK.

cant arm = could be 10+ reasons.. bad gyro.
angle too big.. FC dead.

Finally got home from thanksgiving dinner. Hope you all had a good meal as well.
Thanks for the suggestions!
Booted into betaflight and everything looked good but no connection to controller.
Run my cli dump for this drone and the drone was suddenly able to arm, but no osd.
Flew for about 30 seconds and suddenly the osd appeared?! We'll see how things progress, obviously something took a blow, but I think she's back up and flying for the time being.

Wonder if you've got a crack somewhere. Least it works again. Maybe it'll do like mine and act up one day but never complain again.