run_check $SUDO_HELPER dd bs=1K count=1 seek=$(($sb_offset + 1)) if=/dev/zero of="$TEST_DEV" conv=notrunc
# if corrupting one of the sb copies, copy it over the initial superblock
run_check $SUDO_HELPER dd bs=1K count=1 seek=$(($sb_offset + 1)) if=/dev/zero of="$TEST_DEV" conv=notrunc
# if corrupting one of the sb copies, copy it over the initial superblock