SteamOS 3.6.21 Boot Failure After Update; Reverting to 3.6.20 Resolves Issue

[simlal]

SysInfo

• Steam client version: Latest Jan 20th Patch
• SteamOS version: 3.6.21
• Opted into Steam client beta?: No
• Opted into SteamOS beta?: No
• Have you checked for updates in Settings > System?: Yes

Issue

After updating to SteamOS version 3.6.21, the system becomes unresponsive during boot, displaying only the Steam Deck logo. This persists across multiple reboot attempts. Reverting to the previous SteamOS version (3.6.20) via the boot menu fixes the issue temporarily.

Expected Behavior:
Deck should boot successfully into SteamOS 3.6.21 without hanging on the logo screen...

Actual Behavior:

Post-update, the system hangs on the Steam Deck logo during boot and does not proceed further. Booting into the previous version (3.6.20) works.

Steps to Reproduce:

1. Update SteamOS to version 3.6.21 using either Flatpak/Discover or the steamos-update
2. Reboot the system.
3. Observe the system hanging on the Steam Deck logo during boot.

Temporary Workaround:

1. Reboot the system.
2. During boot, access the boot menu (... + power button).
3. Select "PREVIOUS to boot into SteamOS version 3.6.20.

Additionnal questions and info:

• Boot Menu Behavior: The boot menu defaults to SteamOS 3.6.21 as the "CURRENT" version. Is there a method to set SteamOS 3.6.20 as the default boot option to avoid manual selection each time?

• Maybe I haven't looked enough, but I cannot find how to debug the boot process see whats the err.

• Update Methods: Updating via both Flatpak/Discover and the steamos-update CLI yields the same boot issue.

• I use the deck daily including nix and home-manager (so basically eveyrthing is symlinks! and respect immutability of steamOS), along with various flatpaks and never had any issue.

Thanks!

[matte-schwartz]

A System report as outlined here should have more more details to try and debug it: https://github.com/ValveSoftware/SteamOS?tab=readme-ov-file#reporting-issues

[simlal]

A System report as outlined here should have more more details to try and debug it: https://github.com/ValveSoftware/SteamOS?tab=readme-ov-file#reporting-issues

On my phone now, but I remember one of the various steamos-* cli commands had a sys report in it. Anyways I'll do either one through KDE or the cli and investiguate further this weekend thanks!

[simlal]

so cat sysreport.txt | grep -i error | wc -l gives me 123 lines which when quickly glancing at I get a bunch of different errs from KDE-related (kwin, krunner, x11 etc.) to hardware to kernel stuff. Also grepped for memory but from my very limited skills I cannot tell if some of the kernel reserved memory spaces are wrong or other kernel outputs might seem suspicious. Anyways sent the report to Valve via Gamescope

This is the report from 3.6.20 so maybe I should try to run steamos-update THEN make a steamos-systemreport and diff against one another?

[simlal]

Tried some other strategies to no avail:

1. Disabled quick boot and enabled tests but got stuck there
2. Tried to go into battery storage mode then out, still stuck.

Even though I got most of my configs and tools managed through home-manager, it would still suck to have to go through re-image and rsyncing/setting it back to where it is now.