How to root SonyEricsson Xperia 8 on Linux

Now switch on your phones USB Debugging mode (Settings --> Applications --> Development --> USB Debugging)
Unmount the SD Card (Settings --> SD Card --> Unmount SD Card)
Connect your phone to the computer using the USB cable, when the phone asks chose "Charge Phone".
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(Based on http://forum.xda-developers.com/showthread.php?t=698927 )
Start the adb server as root on your PC. E.g. you'd want to run the following command:

adb kill-server (you must do this to kill the user started server)
sudo adb start-server

Or you can basically do any adb command with sudo to start it. I typically use:
sudo adb devices
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Now back to BASH:

adb push ../Exploits/psneuter /data/local/tmp/psneuter
adb push ../Root/su-v2 /data/local/tmp/su # See Note 1 below
adb push ../Root/Superuser.apk /data/local/tmp/superuser.apk
adb shell
cd /data/local/tmp
chmod 755 psneuter
./psneuter

Once this has run, the adb shell will close and you'll need to reconnect;

adb shell
cd /data/local/tmp
mount -o remount,rw -t yaffs2 /dev/block/mtdblock0 /system
cat su > /system/bin/su
cat superuser.apk > /system/app/superuser.apk
chmod 06777 /system/bin/su
chmod 777 /system/app/superuser.apk
reboot # See Note 2 below

Assuming all went well, your phone is now rooted. When it reboots, you should see a new menu item called "Superuser". The easiest way to check that you've gained root access (as you'll probably need to install this anyway) is to access Android Market and install BusyBox. Once it's downloaded, run the BusyBox Installer app from your menu and follow the instructions, it'll soon tell you if you don't have root!
You can now enjoy the benefits of having root access, such as removing those irritating pre-installed apps like this:

http://androidadvices.com/remove-default-applications-rooted-android-phones/
Notes
1.    The Zip file contains multiple versions of su (e.g. su-v1, su-v2 & su-v3). You may find out which one works. The easy way to find out is to run the command in Note 2, and if necessary adapt the push command to push one of the other versions. Note: su-v2 was found to work on X8.

2.    To check that you've installed the correct version of su, you can run one other command before issuing the reboot command;

    su