Can't boot: /sbin/init exists but couldn't execute it (error -13)

[ciacnorris]

During the last update I read some “device out of space” (or something like that) errors, i think during kernel updates, but both my root and boot devices had a lot of free space.
When I rebooted, I just got a black screen after grub. I removed the quiet option and I got a

Failed to execute /init (error -13)
[...]
Starting init: /sbin/init exists but couldn't execute it (error -13)

error, then a kernel panic, as you can see in the attached pictures.

I have Kubuntu installed on the same machine. What can I do to repair Manjaro?

[ciacnorris]

I have found this: [SOLVED] Kernel panic after latest upgrades / Newbie Corner / Arch Linux Forums

I chrooted into Manjaro, installed a different kernel version (I had to use pacman -S, mhwd-kernel gave me an error about no package selected) and reinstalled grub.
After that, I can boot into Manjaro with the newly installed kernel but booting the old ones still gives the same error.

[freggel.doe]

So boot into Manjaro with the working kernel and reinstall the non-working one.

[ciacnorris]

This worked.