Hi. Command executed focusing on an USB device's whole block:

Are printed the very rows aimed not to be printed; then Sed behaved according to command sed '1,2!d'.

For comparison (whole output is here mentioned) :

# fsck /dev/sdc
fsck from util-linux 2.32.1
e2fsck 1.44.3 (10-July-2018)
ext2fs_open2: Bad magic number in super-block
fsck.ext2: Superblock invalid, trying backup blocks...
fsck.ext2: Bad magic number in super-block while trying to open /dev/sdc

The superblock could not be read or does not describe a valid ext2/ext3/ext4
filesystem.  If the device is valid and it really contains an ext2/ext3/ext4
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
    e2fsck -b 8193 <device>
 or
    e2fsck -b 32768 <device>

Unexpectedly there is no mention of the output resulting from the first command. Regards.