sakoman.com

Thanks to Graeme Gregory (also known as XorA), you can now use a script to automate the tedious process of creating a bootable SD/microSD card:

#! /bin/sh
# (c) 2009 Graeme Gregory
# modified by Steve Sakoman
# This script is GPLv3 licensed!

DRIVE=$1

dd if=/dev/zero of=$DRIVE bs=1024 count=1024

SIZE=`fdisk -l $DRIVE | grep Disk | awk '{print $5}'`

echo DISK SIZE – $SIZE bytes

CYLINDERS=`echo $SIZE/255/63/512 | bc`

echo CYLINDERS – $CYLINDERS

{
echo ,9,0x0C,*
echo ,,,-
} | sfdisk -D -H 255 -S 63 -C $CYLINDERS $DRIVE

umount ${DRIVE}1
mkfs.vfat -F 32 -n boot ${DRIVE}1

umount ${DRIVE}2
mke2fs -j -L rootfs ${DRIVE}2 

You can download a copy of this script here.

To use the script you will need to know what device your SD/microSD card appears as when you insert it into your development machine's card slot.

WARNING: It is very important that you determine the proper device!  Do not proceed if you are not certain, since accidentally specifying your development system's root device would destroy your linux installation.

On my Ubuntu 9.04 machine, the newly inserted card shows up as /dev/sde and that is the device name that will be used in the example below. You should substitute the proper device name for your machine. You can use the mount or dfcommand to see where the card mounts on your machine.

$ sudo mkcard.sh /dev/sde
1024+0 records in
1024+0 records out
1048576 bytes (1.0 MB) copied, 0.766167 s, 1.4 MB/s
Disk /dev/sde doesn't contain a valid partition table
DISK SIZE – 2032664576 bytes
CYLINDERS – 247
Checking that no-one is using this disk right now ...
OK

Disk /dev/sde: 247 cylinders, 255 heads, 63 sectors/track

sfdisk: ERROR: sector 0 does not have an msdos signature
 /dev/sde: unrecognized partition table type
Old situation:
No partitions found
New situation:
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0

   Device Boot Start     End   #cyls    #blocks   Id  System
/dev/sde1   *      0+      8       9-     72261    c  W95 FAT32 (LBA)
/dev/sde2          9     246     238    1911735   83  Linux
/dev/sde3          0       -       0          0    0  Empty
/dev/sde4          0       -       0          0    0  Empty
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).)
umount: /dev/sde1: not mounted
mkfs.vfat 3.0.1 (23 Nov 2008)
mke2fs 1.41.4 (27-Jan-2009)
Filesystem label=rootfs
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
119520 inodes, 477933 blocks
23896 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=490733568
15 block groups
32768 blocks per group, 32768 fragments per group
7968 inodes per group
Superblock backups stored on blocks: 
	32768, 98304, 163840, 229376, 294912

Writing inode tables: done                            
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 20 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.
$