Supermicro X9SCD won't enter BIOS (error code: AB)
Based on user discussions in a thread by Webjunkie in the ServeTheHome Forums it appears that there is a date dependent bug that causes this behavior on some of the Supermicro X9 boards:
It seems like SuperMicro X9 boards with E3v1/v2 CPUs (X9SCL-F, X9SCL+-F, X9SCI-LN4F, X9SCA-F, X9SCM-F, X9SCM-IIF, etc) will not allow you to enter BIOS if the system date is past December 31, 2020. When attempting to enter BIOS, it comes up with a blue screen, and in the bottom right the error code "AB", which apparently means "Setup Input Wait" per SuperMicro documentation. If you clear CMOS, you can get into BIOS. We've tried with the latest BIOS (v2.3) and also older BIOSes with the same results.
Apparently the problem can be worked around by either clearing CMOS to reset the RTC or by booting an OS and using its tooling (eg
hwclock) to set the RTC to a date prior to 2021.
According to their discussion there, Supermicro are aware of the problem:
I just received an update from SuperMicro:
"We are aware of this issue and working internally to address it. I will provide an update once I have more details of BIOS fixes. Please continue to use the manual work-around for now."