Difference between revisions of "Boot from MMC"

Latest revision as of 21:40, 22 September 2011

An updated procedure for both Overo and verdex pro boards can be found here; this procedure is left for reference only.

This section describes how to boot off an MMC/microSD memory card. At the moment it is not possible to boot from microSDHC cards, usually the ones with more than 2GB capacity. This is because the high-speed drivers are not supported. See this thread

Partition the card

Place the card into your reader, and unmount it if it is mounted.

Assuming it is the only mmc card, run fdisk:

sudo fdisk /dev/mmcblk0

Delete any partitions on the disk, in this case there were two:

Command (m for help): d
Partition number (1-4): 1

Command (m for help): d
Selected partition 2

Create the kernel partition:

Command (m for help): n
Partition number (1-4): 1

Command (m for help): n
Selected partition 2

Set it to FAT16 file system:

Command (m for help): t
Selected partition 1
Hex code (type L to list codes): 6
Changed system type of partition 1 to 6 (FAT16)

Create the root fs partition:

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 2
First cylinder (22-984, default 22): 22
Last cylinder, +cylinders or +size{K,M,G} (22-984, default 984): 984

Save the partition table:

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: If you have created or modified any DOS 6.x
partitions, please see the fdisk manual page for additional
information.
Syncing disks.

Format the card

Format the kernel partition

mkfs.vfat -F 16 /dev/mmcblk0p1 -n gum-uimage

Format the rootfs partition

mkfs.ext2 /dev/mmcblk0p2 -L gum-rootfs

Remove and reinsert the card, you should have two mmc drives, one called gum-uimage and one called gum-rootfs

Enable booting from MMC in kernel

If you don't have the user.collection directory setup to change the appropriate conf file, do so like:

mkdir -p $USERBRANCH
cp -r $GUMSTIXBRANCH/conf $USERBRANCH

Edit the conf file for your gumstix, eg for the verdex the file is:

$GUMSTIXTOP/user.collection/conf/machine/gumstix-custom-verdex.conf

Uncomment the line:

MACHINE_FEATURES  += "mmcroot"

The kernel will now build with the necessary drivers

Save the file and rebuild the image:

bitbake -c rebuild task-base-gumstix
bitbake -c rebuild gumstix-kernel
bitbake -c rebuild gumstix-basic-image

Put the images on the card

Copy the uimage file from the working directory to the uimage partition on the card, eg:

cp $GUMSTIXTOP/tmp/deploy/glibc/images/gumstix-custom-verdex/uImage-2.6.21-r1-gumstix-custom-verdex.bin /media/gum-uimage/uimage

Make sure the file on the card is named uimage

Copy the gumstix-factory.script to the uimage partition as well:

cp $GUMSTIXTOP/extras/mmc-root/gumstix-factory.script /media/gum-uimage

Unpack the root file system to the rootfs partition on the card, eg:

sudo tar -xvpzf $GUMSTIXTOP/tmp/deploy/glibc/images/gumstix-custom-verdex/Angstrom-gumstix-basic-image-glibc-ipk-2007.9-test-20090212-gumstix-custom-verdex.rootfs.tar.gz -C /media/gum-rootfs/ 

Unmount BOTH partitions.

Boot!

Place the card in the gumstix and power up.

You should see comething similar to:

U-Boot 1.2.0 (May 10 2008 - 21:22:03) - PXA270@600 MHz - 1604

*** Welcome to Gumstix ***

DRAM:  128 MB
Flash: 32 MB
Using default environment

Hit any key to stop autoboot:  0 
Instruction Cache is ON
Found gumstix-factory.script on MMC...
## Executing script at a2000000
Booting from mmc/microSD...
Detected: 1985024 blocks of 1024 bytes (1938MB) SD card.
Vendor: Man 03 OEM SD "SU02G" Date 06/2008
Product: 1091675832
Revision: 8.0
reading uimage

followed by the rest of the boot process.