Solved T495 Thinkpad hangs on boot acpi0

S

scottro

I have a T495 Thinkpad that I've had since December 2020. It's always worked without problems with FreeBSD. (Multiboot with some Linux systems). The Linux systems all have no problem but suddenly, with no changes made, that is no new ports or other updates, it has started hanging on boot at

Code: 
acpi_acado: <AC Adaptor> on acpi0

I tried booting to a different kernel and checking for BIOS updates but no luck.
I also tried booting from a USB image for an older FreeBSD version, and then, nomadBSD, and GhostBSD, but they all hang in the same place. I'm guessing with GhostBSD as it just shows a GUI but doesn't do anything.
This isn't an important system, used more for playing around, but I can't even reinstall it as a boot USB also hanges at the acpi message. Other suggestions I've seen were to disable some things in sysctl, but I can't get in to do that. Single user mode also hangs in the same place.

It's odd that this happened with no changes made. If anyone has any suggestions, I'd be grateful, though my response might be delayed.

Thanks.
 
I lied. (Though not deliberately). Doing some more searching, I found a BIOS update, installed it, and now it boots. (Though there seems to be an issue with drm-kmod but that's another thread. Marking solved.
 
Hey scottro, it seems that I have the same issue as you, on ThinkPad T495 (20NKS0T10P). I'm already at the current/latest BIOS version (according to dmidecode), which seems to be newer than this thread:

Version: R12ET62W(1.32 )
Release Date: 01/11/2023

Maybe I'm blind but I can't find older BIOS releases on Lenovo's support page.

I've reproduced the problem with 13.2-RELEASE and 14.0-RELEASE install media. Linux boots fine.
 
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