(9900k Vega 64 10.13.6) - Bios post always fails on restart / shutdown

[nineniner]

First, the build would not shutdown or restart (it would just hang on the black screen), until I added emuvariable, now it does restart/shutdown but on every boot, the bios gives me the "post failed last time" error where I have to press f1 to go to bios settings, and then boot from there.

build: 9900k , 32GB RAM, Vega 64 Sapphire, Samsung NVME 1TB, Asus Prime z390-A

 

[pastrychef]

This seems more like a motherboard issue than a software issue. I would try to contact the motherboard manufacturer and see what they have to say.

 

[nineniner]

This seems more like a motherboard issue than a software issue. I would try to contact the motherboard manufacturer and see what they have to say.

it only happens when restarting and shutting down from MacOS

 

[felipefurtado]

Post fail messages usually occurs on a failed attempt to overclock - hence the window with the option to setup bios again pressing F1 or loading default.
Try saving your OC values if you have any, set everything OC settings back to stock and see what happens

 

[nineniner]

Post fail messages usually occurs on a failed attempt to overclock - hence the window with the option to setup bios again pressing F1 or loading default.
Try saving your OC values if you have any, set everything OC settings back to stock and see what happens

I’ll try that, but it’s weird that the OC would crash only when restarting/shutting down. Also, the bios doesn’t reset my OC (which it usually does when an OC causes the fail).

 

[michmcca]

I just completed my first OpenCore install with BigSur. So far everything is working fine with the exception of this problem: bios post always fails on restart or shutdown. I always see the megatrends screen saying press F1 to go to bios. I enabled debugging as shown in the dortania guide, but the resulting file in my EFI partition is always only 262KB, and doesn't capture anything at shutdown or restart. Cany anyone suggest how to debug? Thank you very much!

 

[michmcca]

I found the solution for this problem in the dortania OpenCore post install area:

https://dortania.github.io/OpenCore-Post-Install/misc/rtc.html

You have to use the RTCMemoryFixup kext, and specify a region in the RTC area to omit. It's a laborious process to find exactly what RTC region(s) is/are bad; you have to reboot at least 16 times narrowing the scope of your rtcfx_exclude statement in the boot args, until you find the problem region(s). I was lucky to find only one, and FYI on my ASUS Prime Z390-p it is rtcfx_exclude=59-59.

One more problem I found and resolved: the Visio 4K 39" TV I have been using as a monitor (HDMI only) wasn't working on Big Sur, although lower resolution HDMI monitors work fine. I found that this seems to be a general macos problem that has cropped up in Big Sur:

https://forums.macrumors.com/thread...ing-after-update-to-macos-11-big-sur.2268966/

I installed Catalina using exactly the same OpenCore configuration that worked for Big Sur, and it works like a charm. I'm stoked!