Unable to revert rollback from WSL2 4.19.121 to 4.19.104

[Methylamphetamine]

Environment

Windows build number: 10.0.20150.0
Your Distribution version: Debian 
Whether the issue is on WSL 2 and/or WSL 1: WSL2

Steps to reproduce

in Powershell administrator mode:

wsl.exe --update --rollback
wsl.exe --update --status
wsl.exe --update

Expected behavior

WSL 2 kernel should be updated to the latest (4.19.121)

Actual behavior

After rolling back, the version of WSL kernel is shown to be 4.19.104, and the update status is shown as

WSL automatic updates are on.
The WSL 2 kernel is in the rollback state and is using a previous kernel version.
Kernel version: 4.19.104

But the last update command would only return

No updates are available.
Kernel version: 4.19.104

, which is clearly incorrect because I manually rolled it back from WSL2 4.19.121

[licanhua]

@Methylamphetamine May I ask why you rolled it back and why you want to revert the rollback?
No public interface is provided to revert the rollback and it's by design. Assume we have three release:
A(.104)->B(.121)->C, and when B has problem, customer can rollback to A. When C is shipped, user will be back to mainstream C automatically. wsl --update doesn't allow you to revert back to B(.121) because it's assumed that B has problem and that's why you rolled back.

You are able to do it manually by deleting RollbackKernel in HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Lxss. then run wsl --shutdown with admin and then the kernel is forwarded to .121.
Please note that this procedure is subject to change in the future.

[Methylamphetamine]

@licanhua Thank you for your help and explanation. The procedure worked well.

When WSL 2 kernel .121 was first released days ago, it suffered from problems in its connection with vscode, as described in microsoft/vscode-remote-release#3212 (comment)

I was not too familiar with the current software development procedure, so I chose to rollback the version, thinking that I can revert the rollback with a similar command.

[YevheniiPokhvalii]

In my case, the rollback described above by @licanhua did not help. I am using Windows 11 and tried to update the WSL kernel manually to the latest which led to the broken docker.
What actually helped, is to install the previous kernel version. I downloaded it from this site: https://www.catalog.update.microsoft.com/Search.aspx?q=wsl

P.S. My recommendation, if you use Windows 11, install Windows Subsystem for Linux Preview from the MS Store - it will enable some advanced features like WSLg and don't experiment with the latest kernels manually.

[korenmic]

Unfortunately seems that --rollback was removed as a subflag for wsl --update

That is a darn shame because after a recent wsl --update I have a wsl which 100% of launch attempts just hangs forever and due to the flag removal I cannot perform rollback. Very problematic!

[klibr007]

we can't rollback anymore after mistakingly installing a pre-release I can't rollback. Now I don't even know what to do