Supermicro x12sca-5f stuck on boot

[djeflig]

TL;DR x12sca-5f gets stuck on boot displaying "DXI --USB Initialization..." and code "69"

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In order to investigate why my newly acquired intel arc gpu didn't seem to enter lowest power saving mode I went into bios and changed l1 to l0 l1 and also enabled peer write memory. After this my server won't boot, it gets stuck on the Supermicro boot screen displaying "DXI --USB Initialization..." and code "69". This seems to indicate North Bridge DXE initialization is started. I'm currently unable to enter bios. Ipmi is working, it is recognizing bios version, etc.

I've tried taking out the cmos battery and reset cmos by shorting the pads multiple times. I've left the server off plenty of time before powering it on again. I've taken out all pcie, nvme, usb devices. I've tried to boot up bios recovery mode by putting in a usb with a renamed "Super.ROM" file but the server won't enter the mode. I saw something about needing to press ctrl+home while booting up to enter bios recovery but I'm not sure the boot procedure gets far enough to be able to recognize a usb keyboard.

Any help would be appreciated!

 

[CyklonDX]

The idea with that recovery bios is that it isn't overwritten by future bios upgrades.
Thus it should work, unless there's something else that happened.

I would advise trying removing all memory sticks, and leaving just one (reseating it too), and potentially trying to reseat the cpu.