Same Problem here. Every time I reboot the system, it begins the first time installation again. I'm not able to open Armoury Crate every time.
When it opens, I'm not able to update the model identifier and I've lost control of the motherboard functions. Sometimes I'm able to access the keyboard and mice functions. But after rebooting, it stops working again. I tried reinstall, but the problem persists.
Same issue with Maximus Formula Z690...
It`s always the same: When AC shows an Update, my heart feels like standing still and my Hands began to sweat, because my brain is asking "will all be functional after the update & reboot?"
And it`s always the same answer: NO!