Nokia-N900:~# umount /dev/mmcblk1p1
Nokia-N900:~# sfdisk -uM /dev/mmcblk1 <<EOF
> ,<100>,C
> ,,L
> ,,
> ,,
> EOF
Checking that no-one is using this disk right now ...
OK

Disk /dev/mmcblk1: 31000 cylinders, 4 heads, 16 sectors/track
Old situation:
Warning: The partition table looks like it was made
for C/H/S=*/5/4 (instead of 31000/4/16).
For this listing I'll assume that geometry.
Units = mebibytes of 1048576 bytes, blocks of 1024 bytes, counting from 0

Device Boot Start End MiB #blocks Id System
/dev/mmcblk1p1 4+ 968- 965- 987890+ 6 FAT16
start: (c,h,s) expected (410,4,4) found (4,2,30)
end: (c,h,s) expected (1023,4,4) found (984,4,4)
/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

I've got this, what's wrong?