I've had problems stuck at boot up as well. It started after importing lots of IRs.
I've tried making a backup then resetting to factory defaults and then restoring but still had stuck boot ups.
On top of that after shutting down and trying again it might startup but the scribble strips go blank.
Not sure if that's a related issue.
So, I tried resetting to factory defaults again and reinstalling firmware 1.2 and not restore but start all over building presets, importing IRs.
I now boot up ok but the blank scribble strips thing happens. If I fiddle with global settings footswitches the scribble strips reappear.
Oh, one more thing, output goes silent occasionally when switching between presets. I have to reboot to get sound back.
I have started a support ticket and got a quick reply but no solutions yet.
I bet they are working hard on fixes.
Ah yes, the downside of upgrading.... isn't it fun living on the bleeding edge?
EC