Error in stage 1 while mounting /dev/loop0

I get the following message while booting both the plasma and the minimal installer:

mounting /mnt-root/iso/nix-store.squashfs on /nix/.ro-store
[...] /dev/loop0: Can't open blockdev
[...] unable to read id index table
mount: mounting /dev/loop0 on /mnt-root/ failed: Invalid argument
An error occurred in stage 1 of the boot process, which must 
mount the root filesystem on '/mnt-root' and start the stage 2. 
Press one of the following keys:
  i) to launch an interactive shell
  f) to start an interactive shell having pid 1 
     (needed if you want to start stage 2's init manually)
  r) to reboot immediately
  *) to ignore the error and continue

Iā€™m using a Thinkpad E14

do the shasums not match the downloadable binaries?

e.g. 19b6ca3a7d594bc2da063241491e70109c718bcd0632026fb257052e8fb1af9a nixos-gnome-21.11.336811.0aac710801a-x86_64-linux.iso
vs the file that is downloaded being

I had a similar problem while installing NixOs. In my case, recreating the boot stick as described here with an additional umount afterwards fixed the problem for me, i.e.:

$ sudo dd if=path-to-image of=/dev/sdX
$ sudo umount /dev/sdX