root@dm7080:~# fsck.ext4 -f -v /dev/mmcblk0p2
e2fsck 1.43-WIP (18-May-2015)
dreambox-data: recovering journal
Superblock needs_recovery flag is clear, but journal has data.
Run journal anyway<y>? yes
fsck.ext4: unable to set superblock flags on dreambox-data


dreambox-data: ********** WARNING: Filesystem still has errors **********

root@dm7080:~#
root@dm7080:~# mkfs.ext4 -L dreambox-data -U 65e39b99-3b39-4f47-95ac-43aa4eae2b8a /dev/mmcblk0p2
mke2fs 1.43-WIP (18-May-2015)
/dev/mmcblk0p2 contains a ext4 file system labelled 'dreambox-data'
        last mounted on /data on Wed Jul 17 00:56:53 2019
Proceed anyway? (y,n) y
Creating filesystem with 442363 4k blocks and 110656 inodes
Filesystem UUID: 65e39b99-3b39-4f47-95ac-43aa4eae2b8a
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912

Allocating group tables: done
Writing inode tables: done
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information: done

root@dm7080:~# mkdir /data
mkdir: can't create directory '/data': File exists
root@dm7080:~# mount /dev/mmcblk0p2 /data
mount: wrong fs type, bad option, bad superblock on /dev/mmcblk0p2,
       missing codepage or helper program, or other error

       In some cases useful info is found in syslog - try
       dmesg | tail or so.
root@dm7080:~#