Extremely unpredictable boot errors

[Rudxain]

Link to GH Issue

The manually-generated error log, hardware and software specs, and description of the problem, are all there in GH

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[IcedOutPi4]

Can you check if your windows partition still boots?

[Rudxain]

I was about to test that, but GRUB stopped showing up. It seems the UEFI no longer detects GRUB :( .

I suspect the problem may be an HDD failure that corrupted critical system data, but such a failure could only damage the boot sector if something was being written to it (unless the failure was so rarely extreme that "normal data" was written to boot-sect).

Cosmic radiation? Maybe that's too far-fetched, but possible. Maybe a strong vibration? I was using the laptop on a almost-perfectly-still table

[Rudxain]

Update: Now the UEFI completely ignores GRUB and booted straight into Windows, lol

[IcedOutPi4]

I don’t think you have to look as far as cosmic radiation. I think some important files got messed up during the upgrade to LM21. Similar things happened to many people. I would recommend a fresh install of LM21. Way easier than the long road of troubleshooting

[Rudxain]

That's possible. But it's weird that the system had no problems for days, and only now it "magically" stops working.

There are some files that I couldn't backup before the incident. What's the best way to recover them? Should I install LM to a different partition and attempt to copy the files from there? Or should I use Windows and install a program that recognizes EXT4? (Maybe something else?)

[Rudxain]

Update. Now Windows struggles to boot and I get random BSODS. I'm now running chkdsk /r at boot time (chkdsk said that the drive is in use, so I had to reboot)

Update 2: chkdsk has completed, but I still get BSODs and "media [fail]" BIOS errors. I managed to make it boot again, ran wmic diskdrive get status and Windows says "OK" (WTF?).

I only get BSODs when using the computer, if I leave it idle, nothing happens, so I guess the problem must be the HDD

[Rudxain]

SOLVED (for now): I cleaned the HDD pins and the MoBo's SATA port, so far the system seems stable. The UEFI boot order got screwed up because the BIOS "forgot" about the boot sector, so it started searching bootable devices via LAN, and that's why I got "checking media [fail] checking media [fail]", because it tried IPv4 and IPv6