Sorry mate, didn't see your reply until after I posted. I don't really follow, sorry. umount /dev/mmcblk1p1 sfdisk -uM /dev/mmcblk1 << EOF If correct? mmcblk1 is the SD card and the p1 is the partition 1? So are you saying it would be something like this: umount /dev/mmcblk1p1 sfdisk -uM /dev/mmcblk1 << EOF ,3500,C ,,L ,, ,, EOF umount /dev/mmcblk1p2 sfdisk -uM /dev/mmcblk1 << EOF ,1900,C ,,L ,, ,, EOF and the 3rd partition would be the remaining?