yes, the kernel repo rewrote its history in this period and is known to have broken historical manifests

i've created a dummy branch named "old-next-11085-crbug-898204" to point to 2266c3bc5c015cb15a3d2ff1150d8150a97f8860 which i think should fix syncing that range.

if you see any other historical manifests break, please re-open with links to the specific versioned manifest like you did in comment #0 (which was very helpful).

Is the dummy branch pushed to the server?
I haven't saw the branch https://chromium.googlesource.com/chromiumos/third_party/kernel/+refs
and this link is still 404 https://chromium.googlesource.com/chromiumos/third_party/kernel/+/2266c3bc5c015cb15a3d2ff1150d8150a97f8860

i created the branch in kernel-next.  the manifest you linked to is pulling 2266c3bc5c015cb15a3d2ff1150d8150a97f8860 from kernel-next.  so what manifest are you using that wants 2266c3bc5c015cb15a3d2ff1150d8150a97f8860 in the kernel repo ?

No, the manifest is pulling the said CL from kernel, not kernel-next.

The command line to reproduce this issue:
$ repo init -u https://chrome-internal.googlesource.com/chromeos/manifest-versions -m buildspecs/71/11085.0.0.xml --repo-url https://chromium.googlesource.com/external/repo.git
$ repo sync
error: Cannot fetch chromiumos/third_party/kernel (GitError: chromiumos/third_party/kernel update-ref: fatal: 2266c3bc5c015cb15a3d2ff1150d8150a97f8860^0: not a valid SHA1
)

I did that already by creating all the necessay branches in the kernel repository, as part of the fix for  issue 892292 . Since then, someone went in and deleted all those branches. I am not going to do the work again since I have to assume that this someone (or some automated script) will undo my work again. Whoever removed the branches, or caused those branches to be removed, should be the one to re-create them. I'll leave this bug open for a day and then close as WontFix.

... well, unless vapier wants to find a different solution. Sorry, I had the impression this was assigned to me.

sorry, i misread the manifest line when it said "kernel-next" in the path when i should have been looking at the line

i've pushed the branch mentioned in comment #2 to the kernel.git repo now which fixes syncing this manifest