Note: This guide is aimed only at advanced users. Messing something up during the installation might break your device, so do not attempt anything, unless you are sure you can handle it.
With the “hackability” of the N900 there’s quite a lot of alternative mobile operating systems available for it. We already covered NITDroid and Mer, and today I’m going to direct you through the installation of another mobile system I find very promising, SHR.
SHR is a GNU/Linux based OS that is available for quite many devices, all of which can be found by surfing through the project’s wiki. Surely, for a mobile OS, it can perform phone calls, end SMS, use GPS all while being a well-working GNU/Linux system, just like Maemo is. So, onto installation.
You will require all these things:
A Nokia N900, updated to a latest PR (which is 1.3).
A MicroSD card with a large capacity (at least 4 gB).
Class and brand of the SD card plays a huge role here. A class 10 card is preferable. Cards are mostly “what-you-pay-is-what-you-get”, so the more expensive card is usually the better one.
Get U-boot from Extras-devel, if you don’t have it. Reboot the phone to verify installation, there should be a mention of U-Boot and usually a picture of Tux (a penguin) in a corner. Make sure to disable extras-devel after installing U-boot.
The guide assumes you’re using a *nix machine. Windows users can use a small GNU/Linux LiveCD for following the guide.
Now, slot your MicroSD card into your cardreader. You’ll want to repartition it.
Verify the name of the SD device with
sudo fdisk -l
It should look like /dev/sdX with X being a letter. Make sure it’s the correct device name by mounting it or otherwise checking.
If you have automounting enabled, unmount the card:
sudo umount <card_mount_point>
Run fdisk on the card:
Obviously, replace sdX with your actual device name. For testing purposes, just a single ext3 partition is okay:
Command (m for help): n
p primary partition (1-4)
Partition number (1-4): 1
First cylinder (1-4865, default 1): 1
Last cylinder or +size or +sizeM or +sizeK (1-4865, default 4865): 4865
Command (m for help): t
Partition number (1-4): 1
Hex code (type L to list codes): 83
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Finally, format your partition into ext3:
mkfs.ext3 -b 4096 /dev/sdX1
Once you finished repartioning, mount your newly made partition:
sudo mount -t ext3 -o rw /dev/sdX1 <mount_point>
(<mount_point> being the directory, where you wish the card to be mounted)
cd into the mountpoint:
and extract the SHR image you downloaded earlier into it:
sudo tar xvzpf /path/to/shr-image-nokia900.tar.gz –numeric-owner
Remove the card from your cardreader, shut your N900 down, slot the card into it. Turn it on with the keyboard slider open. Your N900 shall now begin booting SHR. If you want to boot into Maemo instead, turn it on with the slider closed.