Posting here in an attempt to raise an issue being experienced by me - and a multitude of other users posting on overclock.net. MZ690 Hero with 12900K and 2x16MB Corsair Dominator 6000C36.
Back in early December, beta UEFI 2301 for the Z690 boards was made available on the ROG/Strix Z690 thread there. I tried it, hoping it would solve an issue encountered (and reported) with the 2202/2203/2204 series. Ironically, it seems as though it *did* solve that problem.
However, I almost immediately found that a previously 24/7 rock stable system was now suffering 4 or 5 BSODs per day, and would also not reliably resume from standby - either rebooting or halting POST on a variety of Q-Codes (of which 0x55 is the most common, so memory instability). Other posters on OC.net who tried it were also reporting 0x55 a lot. The frustrating thing is that the system was/is stable under load/stress/benchmarking, but will randomly BSOD while idling or carrying out low demand tasks. Updating the ME firmware to 126.96.36.1991 hasn't changed any behaviours either.
After initially discovering these issues I tried to flash back to a stable release build - and couldn't. Any attempt to use either EZFlash or USB FlashBack fails (EzFlash giving the "Selected file is not a proper BIOS" dialog, USB FB gives the solid blue LED after a few seconds). Again, other posters reporting inability to flash back - including some with dual BIOS boards who were experiencing stability issues with the 'other' BIOS after flashing 2301.
Nothing I have tried since has either got the system back to full stability, or enabled regression to a stable UEFI build. I seem to have eliminated the BSOD in Windows by dropping memory bus speed back (from 6200 to 5600MHz) *and* raising the memory controller, RAM VDD and VDDQ voltages. However it *still* won't reliably resume from sleep or hibernation. It either hangs during POST, or reboots while resuming the OS. Which is a major pest as I can't even trust the system to wake by itself and carry out scheduled tasks while I'm away from it.
Instability or other unpredictable behaviour is a risk we all take when trying a beta. However, there was no advance warning given that this build has a regression block on it, meaning we are unable to flash back to a stable build. That sucks a bit.
ROG support - can you please provide some tools (or a modified UEFI with the regression block removed) that will enable those of us currently stuck with 2301 to flash back to a stable one, or at least will fix whatever is clearly causing significantly reduced memory (or other platform) stability for a significant base of users who tried it? Thanks 🙂