maemo.org - Talk - Booting from the MMC card (nokia 770)

I've no blog/web page to publish the step by step guide...So i'm posting it here...
How to boot the Maemo reference root filesystem from the MMC

What you need:
1) The maemo Dev Platform rootfs :
(Warning:This fs is for developing..All user utilities are stripped out..The "normal" image is here, but i've not tested with this..

2)The flasher tool

How to do it:
The first steps are just like the ones shown in the Maemo wiki:

Code:

sudo modprobe mtdblock

$ sudo modprobe mtdram total_size=65536 erase_size=256

$ sudo modprobe jffs2

$ sudo modprobe loop

$ sudo losetup /dev/loop0 /pathtoimage/rootfs.jffs2

$ sudo dd if=/pathtoimage/rootfs.jffs2 of=/dev/mtdblock0

$ mkdir /mnt/jffs2

$ sudo mount -t jffs2 /dev/mtdblock0 /mnt/jffs2

Note : rootfs.jffs2 must be the name of the file you downloaded in step 1

Code:

$ cd /mnt/jffs2

$ sudo tar cvzf /my_path/myRootImage.tar.gz .

$ cd

$ umount /mnt/jffs2

Next step is to format the mmc (i'm supposing here your mmc is detected as /dev/sda1...this may vary..)

Code:

$ mkfs.ext3 /dev/sda1

$ mkdir /mnt/mymmc

$ mount -t ext3 /dev/sda1 /mnt/mymmc

$ cd /mnt/mymmc

$ tar xvzf /my_path/myRootImage

All this has just been convert and uncompress the root filesystem onto your mmc.

Telling the nokia to boot from the MMC:
Use the flasher tool.Shut down the 770, unplug the battery if plugged in, and connect it to the computer with the USB cable.
Exec this (supposing flasher is in the same directory where your shell is)

Code:

$./flasher --set-root-device mmc --reboot

Turn on the device.After flasher does its job, you should boot from the MMC.

You can always reset the root partition with:

Code:

$./flasher --set-root-device flash --reboot

There's also the option to boot from USB, which i can find useful to attach an external USB disk to have all the tools you may need for developing/testing.(Great USB fix by ThoughtFix (m8, works like a charm!) and enabling usb host mode needed)

Booting from the MMC is great to test things like new kernels or apps you just downloaded.

Once you've formatted your MMC as ext3, the system in the flash will not auto-recognize the mmc (or the partition you used to put the new fs in).
By gaining root (see maemo website), and with a xterm (see maemo website), you can mount it by hand.
If then, you cd to it, and chroot in it...you'll be able to launch apps both in the "flash root", and the "mmc root".

TODO: The file /mnt/initfs/linuxrc has a "boot menu" that should appear if rd-mode is enabled (i think..not looking at it right now).Is it possible to enable that menu at boot time , so root (and other options) can be set without the flasher?