Watching this topic as well. Just tried updating my Amplifi 75 via iPad and gave it a few hours. Finally returned "update failed" and has been unresponsive every since.
No luck connecting to it via Mac version (on High Sierra) of Line 6 Updater either.
Tried powering up holding Tone+Tap without luck.
Also tried factory reset Master Volume + Tone. Nothing.
The A and D LEDs are lit, B is dimly lit, C is very dimly lit or off, Bluetooth LED is dim.
Cautiously optimistic that there's a solution (bought it a year ago, so well outside the 90 day warrantee), otherwise I'll just tear it apart for spare project parts. Can't let it go to waste!
