[arch-general] Heads up: After system update, LUKS fails with certain BIOS versions

[LuKaRo]

Hello everyone,

My desktop machine didn't shut down cleanly yesterday after I did system 
upgrades, hanging at closing my dmcrypt devices. I power-cycled after 10 
minutes, and today it wouldn't boot, again hanging at the 
[encrypt]-hook. I tried cryptsetup open, luksOpen, luksDump and isLuks 
from a fresh 2020-05-01 archiso, all with --debug, with multiple 
encrypted internal drives, all hanging after printing the header 
checksum. So I couldn't access any of my drives anymore. dd if=/dev/sdxy 
of=/dev/null worked fine for all of them, though.

I already thought my header got corrupted somehow and my data was lost, 
until I remembered I had some output in dmesg for several months now: 
`rdrand gives funky smelling output`. I gave it a shot and updated my 
BIOS, and hooray, my system booted up just fine. Back in my system, I 
noticed cryptsetup 2.3.1-1 -> 2.3.1-3 and linux 5.6.7 -> 5.6.8 in 
yesterday's update. So probably something has changed in that update 
that causes an issue connected with the old BIOS version.

This was definitely not the solution I expected, and therefore I want to 
share it, as others might be affected as well. My Mainboard is an Asus 
Prime X470-Pro, CPU is AMD Ryzen 7-3900x. Updating to BIOS v5406 fixed 
the issue. So if you get similar issues, don't worry, your data might 
not be lost :)

Kind regards,
LuKaRo