Hello,
I got the Crosshair IV Hero AM4 mainboard recently, and so far it's running great.
While setting up and and testing the max possible RAM speed(Ended up at DDR4-2666 for a 32GB 2 Module Dual-Rank kit), I ended up in a situation where it wouldn't POST anymore.
For some weird reason, the Clear CMOS button on the back of it didn't seem to have any effect though. All the lights go out on the board, but it still wouldn't boot again, even after turning off and back on again on its own multiple times on the next boot.
I eventually got it to boot up again, by trying various combinations of removing system power, pushing Clear CMOS and booting via the safe boot button on the mainboard.
To my surprise when I got back into the BIOS, all my settings, even the too high RAM frequency, was still there, completely unchanged, but it booted in safe-mode, with low RAM speed. The only thing that actually got reset was the system time, no other setting was affected.
Just pushing the safe boot button on its own also doesn't work. Only the combination of some of the things I did worked out in the end.
Is this intended? It makes fiddling with settings rather scary if there is no clear and always working way to recover.