Find your device image here:__

http://www.cyanogenmod.com/devices

Here is for Sony Ericsson Xperia Play, etc.

http://www.cyanogenmod.com/devices/sony-ericsson-xperia-play-gsm

If you see boot-device_code.img for your prototype, also download it to use for the boot.img.__

Push the image zip file to your phone storage.__

Your device should be unlockable and unlocked, check here for Sony Ericsson Arc, etc

http://unlockbootloader.sonymobile.com/__

At least you should get fastboot and android driver to your PC.__

If you work on a Linux system, it’s OK to just get a Linux version fastboot.__

Steps:__

Power on your device, while press the unlock button.__

Some unlock button according to different devices.__

·         __Menu button (for Xperia™ arc, Xperia™ arc S, Xperia™ neo, Xperia™ neo V, Xperia™ pro).__

·         __Search button (for Xperia™ PLAY).__

·         __Volume up button (for Xperia™ mini, Xperia™ mini pro, Xperia™ ray, Xperia™ active, Live with Walkman™, Xperia™ S).__

Check if fastboot can work on the device, version 0.3 means you can continue.__

fastboot -i 0x0fce getvar version____

version: 0.3__

finished. total time: 0.000s__

Then flash the boot image.__

fastboot flash boot boot.img____

sending ‘boot’ (5290 KB)…__

(bootloader) USB download speed was 9707kB/s__

OKAY [  0.562s]__

writing ‘boot’…__

(bootloader) Download buffer format: boot IMG__

(bootloader) Flash of partition ‘boot’ requested__

(bootloader) S1 partID 0x0000000C, block 0x00000280-0x00000BeC__

(bootloader) Erase operation complete, 0 bad blocks encountered__

(bootloader) Flashing…__

(bootloader) Flash operation complete__

OKAY [  1.109s]__

finished. total time: 1.672s__

__Reboot your device, press volume done button many times during booting. (* indeed, once is OK just after the front keypad is lighten.)

__

Using the menu with volume up/down and back to navigate, and Home (on some devices it is Power) button to select, wipe your user data, wipe your cache, and then install update zip file. Wait for the update is finished, then back to upper menu and select to restart the device.__

Now you have Jelly Bean, which is now Android 4.1.1.