Re: HOWTO: USB boot on 8 GB RPi4 with no SD card

[Greg Troxel <gdt%lexort.com@localhost>]

mlelstv%serpens.de@localhost (Michael van Elst) writes:

>>"mount_ffs: /dev/dk1 on /mnt: incorrect super block"
>
> Yep. fsck recognizes the filesystem and doesn't report an error,
> but mount fails.
>
> The reason is that the image is truncated.
>
> The ffs partition in the current image is 2326528 disk blocks.
> The superblock specifies a size of 145792 frags = 2332672 disk blocks.
>
> The mount operation checks access to the last block unless you
> mount read-only. So mount -o ro actually works on the truncated
> image.

It seems to be that it would be good for fsck to also check access.   I
may well not be understanding something, but I expect that if fsck is
ok, the filesystem is ok.

(I realize that having fsck read every single block, or even every
single block in use by any file, wouldn't be reasonable.)