Can't mount SD card partition to /boot, but works elsewhere

Question

I have a server (DL360p if that matters) that boots off the internal SD card slot. For some reason, the /boot filesystem failed after boot. I have pulled the SD card into my laptop and ran filesystem checks, all is fine, the files are there. I have since put the SD card back into the server slot, and it is successfully detected with no filesystem error.

I then tried to mount the partition on /boot, but it won't work. I can mount it elsewhere though, and the files are there (this snipped is done with dmesg -w &):

root@dikkenek:/# rmdir boot
root@dikkenek:/# mkdir boot
root@dikkenek:/# mount /dev/sde1 /boot
root@dikkenek:/# [4983170.551071] EXT4-fs (sde1): mounted filesystem with ordered data mode. Opts: (null)

root@dikkenek:/# ls boot
root@dikkenek:/#

Elsewhere:

root@dikkenek:/# mkdir boote
root@dikkenek:/# mount /dev/sde1 /boote
root@dikkenek:/# [4983211.174716] EXT4-fs (sde1): mounted filesystem with ordered data mode. Opts: (null)

root@dikkenek:/# ls boote
config-5.10.0-10-amd64  config-5.10.0-15-amd64  grub                        initrd.img-5.10.0-11-amd64  initrd.img-5.10.0-16-amd64  System.map-5.10.0-10-amd64  System.map-5.10.0-15-amd64  vmlinuz-5.10.0-10-amd64  vmlinuz-5.10.0-15-amd64
config-5.10.0-11-amd64  config-5.10.0-16-amd64  initrd.img-5.10.0-10-amd64  initrd.img-5.10.0-15-amd64  lost+found                  System.map-5.10.0-11-amd64  System.map-5.10.0-16-amd64  vmlinuz-5.10.0-11-amd64  vmlinuz-5.10.0-16-amd64
root@dikkenek:/#

I have this line in my /etc/fstab and the UUID matches:

root@dikkenek:/# grep boot /etc/fstab
# /boot was on /dev/sde1 during installation
UUID=2ea55b27-d7d5-4e0d-8734-f69d92cb8407 /boot           ext4    defaults        0       2
root@dikkenek:/# blkid /dev/sde1
/dev/sde1: UUID="2ea55b27-d7d5-4e0d-8734-f69d92cb8407" BLOCK_SIZE="4096" TYPE="ext4" PARTUUID="fd5af08d-01"

mount -a doesn't fail but doesn't mount either.

How come it won't mount on /boot? I can't reboot now, or upgrade my kernel.

The server runs Debian 11 bullseye (Linux 5.10.0-16-amd64) if that matters.

Edit: another test:

root@dikkenek:/# mount --bind /boote /boot
root@dikkenek:/# ls boot
root@dikkenek:/# ls boote
config-5.10.0-10-amd64  config-5.10.0-15-amd64  grub                        initrd.img-5.10.0-11-amd64  initrd.img-5.10.0-16-amd64  System.map-5.10.0-10-amd64  System.map-5.10.0-15-amd64  vmlinuz-5.10.0-10-amd64  vmlinuz-5.10.0-15-amd64
config-5.10.0-11-amd64  config-5.10.0-16-amd64  initrd.img-5.10.0-10-amd64  initrd.img-5.10.0-15-amd64  lost+found                  System.map-5.10.0-11-amd64  System.map-5.10.0-16-amd64  vmlinuz-5.10.0-11-amd64  vmlinuz-5.10.0-16-amd64

I'm afraid I'll have to reboot to fix this...??

Answer 1

I was able to complete apt updates by removing /boot, mounting /dev/sde1 on /boote and then adding a symlink from /boot to it.

Apt didn't flinch, it could run grub updates and other system updates.
I'm going to assume that once the server reboots, whatever problem it had mounting will be gone, and I will be able to boot on the new kernel seamlessly.