Sorry to see you’re having trouble.
The good news is, the lights on the back are indicating that your H90 is OK; the update process for the internal firmware that controls the front panel probably got interrupted during the last downgrade; now, even though it looks like nothing is happening, it is doing the “fallback” version of the front panel update.
Plug the H90 back in, and let it sit for ~5 minutes. That should give the internal firmware enough time to program, and you should see the H90 display come back to life.
