/home/user # umount /dev/mmcblk1p1
/home/user # sfdisk /dev/mmcblk1 <<EOF
> ,,c
> EOF
Checking that no-one is using this disk right now ...
OK

Disk /dev/mmcblk1: 486192 cylinders, 4 heads, 16 sectors/track
Old situation:
Units = cylinders of 32768 bytes, blocks of 1024 bytes, counting from 0

   Device Boot Start     End   #cyls    #blocks   Id  System
/dev/mmcblk1p1          0+ 486191  486192-  15558136    b  W95 FAT32
/dev/mmcblk1p2          0       -       0          0    0  Empty
/dev/mmcblk1p3          0       -       0          0    0  Empty
/dev/mmcblk1p4          0       -       0          0    0  Empty
New situation:
Units = cylinders of 32768 bytes, blocks of 1024 bytes, counting from 0

   Device Boot Start     End   #cyls    #blocks   Id  System
/dev/mmcblk1p1          0+ 486191  486192-  15558143+   c  W95 FAT32 (LBA)
/dev/mmcblk1p2          0       -       0          0    0  Empty
/dev/mmcblk1p3          0       -       0          0    0  Empty
/dev/mmcblk1p4          0       -       0          0    0  Empty
Warning: no primary partition is marked bootable (active)
This does not matter for LILO, but the DOS MBR will not boot this disk.
Successfully wrote the new partition table

Re-reading the partition table ...

If you created or changed a DOS partition, /dev/foo7, say, then use dd(1)
to zero the first 512 bytes:  dd if=/dev/zero of=/dev/foo7 bs=512 count=1
(See fdisk(8).)
/home/user # sync
/home/user # mkfs.vfat /dev/mmcblk1p1
mkfs.vfat 3.0.1 (23 Nov 2008)
37
#####################################/home/user # sync
/home/user # sfdisk -d /dev/mmcblk1
# partition table of /dev/mmcblk1
unit: sectors

/dev/mmcblk1p1 : start=        1, size= 31116287, Id= c
/dev/mmcblk1p2 : start=        0, size=        0, Id= 0
/dev/mmcblk1p3 : start=        0, size=        0, Id= 0
/dev/mmcblk1p4 : start=        0, size=        0, Id= 0
/home/user #