Performed a usual system update which involved new packages such as linux kernel 5.17, flatpak and a few others. The GUI updater recommended a “Restart and update” which I did. Unfortunately, the installation froze. Waited for 5 mins before doing a hard reboot.
Unfortunately, on restarting the system, it fails to boot even older kernels such as 5.16. The boot error is shown in the screenshot below.
Starting Switch Root...
Failed to execute /sbin/init
Failed to execute fallback shell
I suspect you failed to wait long enough for the update to complete and probably have a corrupted boot image due to interrupting the update process. An offline update can take some time for the boot portion to complete and should never be interrupted.
You can usually fix that by booting from live USB then mounting the system filesystems and using chroot to work within the installed system and perform recovery actions. You probably should do an fsck on each of the file systems before mounting just in case the file system itself is corrupted and not just a file.