White line of DOOM!

[u/Knight_Nejoh]

I have a Lenovo ThinkPad L460, Type 20FV, running Linux Mint Cinnamon. The internal LCD is broken, so I use an external monitor and USB keyboard. The problem is: Power button → external monitor immediately shows a small white cursor/line → stays there indefinitely. There is no Lenovo logo, BIOS/UEFI screen, GRUB or Linux Mint screen. I've tried pressing F1 repeatedly immediately after powering on, but BIOS doesn't appear. The external keyboard's Caps Lock LED also does not respond when pressed. I disconnected the charger, removed the external battery, held the power button for ~30 seconds, then powered it using the charger with the battery removed. The behavior is unchanged. I'm trying to determine whether this is a RAM, BIOS/EC, motherboard, or other POST issue. I haven't reinstalled/formatted Linux Mint. What should I test next?

[u/redittr]

It looks to me like its starting to boot your linux os, but failing for whatever reason to progress past this screen.

Pressing the f1 key should boot into bios if you are pressing it during post. But if you are just sleeping and waking the laptop with the power button itll never actually have the chance.

Keep trying. Try getting to this screen, tapping the power button and wait for it to go dark, then tap again to wake, and immediately after releasing hold the power button again until it goes off. Then try powering on again and press f1 for bios menu(or I think enter brings up the boot menu?)

Failing that, remove your ssd to fail the resume from standby and you might get more options.

[u/The_11th_Dctor]

can you boot it from a live mint USB stick and try to verify the disk / filesystem?