Ok I made it this far: /home/user # umount /dev/mmcblk1p1 /home/user # sfdisk -uM /dev/mmcblk1 <<EOF > <14100>,C > L > > EOF Checking that no-one is using this disk right now ... OK Disk /dev/mmcblk1: 490432 cylinders, 4 heads, 16 sectors/track Old situation: Units = mebibytes of 1048576 bytes, blocks of 1024 bytes, counting from 0 Device Boot Start End MiB #blocks Id System /dev/mmcblk1p1 0+ 15325 15326- 15693816 b W95 FAT32 /dev/mmcblk1p2 0 - 0 0 0 Empty /dev/mmcblk1p3 0 - 0 0 0 Empty /dev/mmcblk1p4 0 - 0 0 0 Empty trailing junk after number sfdisk: bad input /home/user # /home/user # did i put the size to high?