I tried again 2day in Terminal on my Mac which SSH connected to N900, and give me feedback like this: Nokia-N900:~# unmount /dev/mmcblk1p1 -sh: unmount: not found Nokia-N900:~# sfdisk -uM /dev/mmcblk1 << EOF > ,<100>,C > ,,L > ,, > ,, > EOF Checking that no-one is using this disk right now ... BLKRRPART: Device or resource busy This disk is currently in use - repartitioning is probably a bad idea. Umount all file systems, and swapoff all swap partitions on this disk. Use the --no-reread flag to suppress this check. Use the --force flag to overrule all checks. Nokia-N900:~# unmount /dev/mmcblk1p1 -sh: unmount: not found Nokia-N900:~# mkfs.vfat /dev/mmcblk1p1 -n sdcard mkfs.vfat 3.0.1 (23 Nov 2008) mkfs.vfat: /dev/mmcblk1p1 contains a mounted file system. Nokia-N900:~# mke2fs -j -m0 -L NITDroid /dev/mmcblk1p2 mke2fs 1.41.3.maemo0 (12-Oct-2008) Could not stat /dev/mmcblk1p2 --- No such file or directory The device apparently does not exist; did you specify it correctly?