Z170 Extreme6 1.60-1.70 BIOS Issues

Ok spent a few days trying to fix this issue and going back the P1.50 BIOS was the only thing that corrected it.

There is an issue with BIOS version 1.60 and 1.70, its slightly fixed with the newest beta BIOS but you can't use OC memory (or at least mine)

Since I upgraded to 1.60 my computer would not shut down or restart correctly, I had to do a PSU hard reset to get it to boot.. On shut down it would go into low power mode and not complete shut down, additionally when restarting the PC it would read a 00 Debug code and not detect the CPU and not turn on. With the new 1.73 BIOS it works but I cannot use my Memory OC despite my memory being on the support list. I contacted Tech Support they suggested rolling back to 1.50 and it works fine.. just putting this out there if anyone else has a similar issue. hopefully ASRock will work this out in the near future. 

If you're OC'ing, did you lower it/them back to stock before flashing? Should always do that. Reset UEFI or whatever it is in your BIOS.

1.70 includes an ME update so you should have probably also uninstalled your current Intel INF and ME, rebooted, and installed the latest ones.

Try lowering it back to stock and reflash 1.60 using Instant Flash.

Or, if the original BIOS the board came with supported your CPU, look in your manual and do a Secure BIOS Backup to the A BIOS. Then rejigger the A<>B switch and flash A with 1.60.