Comment 7 for bug 1895329

It could be a race, this is the code that creates the partition and filesystem:

    echo "start=$start" | sfdisk --no-reread -q $DEVICE -a || return
    for d in ${DEVICE}$newpartno ${DEVICE}p$newpartno ${DEVICE}-part$newpartno; do
        if [ -e $d ]; then
            mkfs.ext4 -q -L "$(root_persistence_label)" -F $d
            break
        fi
    done
    udevadm trigger
    udevadm settle

But my understanding is that sfdisk (with the options we use here) doesn't return until it has told the kernel about the new partitions.

I also doubt that the changes to image mastering made a difference here and suspect it was some other change that coincidentally happened around the same time but who knows. (If the partition wasn't being created, I could quite easily believe the mastering changes would make a difference). I'll see if I can reproduce on my laptop tomorrow.