I bought a used Dell Latitude 7490 installed all updates in Windows 11 (including bios and firmware) and switched to Debian 13 afterwards. Unfortunately, since then for about every 20 boots it only got past the LUKS prompt once or twice. Most of the time it shows the LUKS prompt and before I can even type in the pass phrase the whole screen shows colorful noise while the caps lock key blinks white much more often than any signal documented as an error code in the manual. The caps lock stops blinking after a while but the noise stays and I can only interrupt it by long-pressing the power button.
I can use the UEFI reliably for as long as I want and when the system can get past the crucial moment during the boot routine it works flawlessly. But unfortunately this is very rarely the case. Running the systems diagnostics didn't uncover any issues. I tried to boot an older kernel and the recovery mode, but to no avail. Then I replaced the M.2 SSD and later the RAM for in other devices proven working parts but both didn't change the behaviour.
I am having a hard time finding what causes the issue. The inside looks very clean. So I don't expect that something creating a shortcut is likely to be the issue. Also it seems somewhat suspicious that it does always fail at the same stage in the booting process. I am actually not convinced any more if it will ever boot again since I have tried so many times and haven't got through for a long time now. (Maybe it actually only works after having used a live system before.)
I red that firmware flaws could cause such behaviour. At the moment BIOS version 1059v00 runs. Would you expect that installing an older BIOS version could help?
A friend pointed out that it might be related to switching the graphics mode during boot. I am not sure what I should or could do with that information since the system wouldn't be of much use in this case without the GUI.
Statistics: Posted by Onsemeliot — 2026-02-05 18:09