kern/60140: NetBSD 11.0-RC2 boots to black screen on Thinkpad X240 more often than not

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>Number:         60140
>Category:       kern
>Synopsis:       NetBSD 11.0-RC2 boots to black screen on Thinkpad X240 more often than not
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Mar 28 22:10:00 +0000 2026
>Originator:     Daniel
>Release:        11.0-RC2
>Organization:
>Environment:
>Description:
The majority of the time I boot into NetBSD 11.0-RC2 after installing it on my laptop, I reach the EFI boot screen, either select "1" or let it finish on its own, it displays several numbers on the screen as usual, and then goes to a black screen and never does anything else no matter how long it's left for.

Importantly, this doesn't happen *every* time the laptop is booted. Sometimes, it boots just fine, and I haven't found any rhyme or reason for why this happens.

No factors I have control over seem to determine whether or not the laptop boots successfully. Waiting on the boot options menu, waiting for an extended period of time between boots, etc all seem to have no effect on when it does or doesn't happen.

This happens in both the installer and the fully installed OS. I have tried re-flashing the install media multiple times, and have verified that the checksum of my install media is correct, and yet I still experienced this issue with consistent inconsistency across all attempts.

These boot issues do not happen under other operating systems such as Linux.

I am unsure of how to diagnose this issue, and I'm also not 100% sure this is a kernel issue, that just seems like the most logical thing that would be failing here. Please direct me on how to collect any useful information.
>How-To-Repeat:
Exact repro conditions unknown
>Fix: