My old “back up” phone, a Sony Xperia Arc LT18i, was rendered useless because of some annoying error. Every 2 seconds it would pop up on the screen: “Unfortunately, the process com.android.phone has stopped“. This probably happened because I removed the T-Mobile SIM card and the phone was carrier locked. I tried resetting (and factory resetting) the phone in every possible way. Nothing would work. So I decided it was time to try a different approach and flash a new ROM on it: CyanogenMod. As a bonus, it upgrades my phone to a newer Android: from 4.0.1 Ice Cream Sandwich to 4.1.2 Jelly Bean.

I found the instructions on this CyanogenMod Wiki: Install_CM_for_anzu. I recommend reading this before attempting the install yourself.

This was my set-up:

• Sony Xperia Arc LT18i
• 8GB SD-card (in the phone)
• PC running Linux Mint 17.3 64-bit
• USB cable between the phone and the PC

Here you can read how I succesfully installed CyanogenMod 10 on my Xperia Arc.

Note that this doesn’t automatically install the Google apps like the Google Play store. They need to be installed seperately if you want those, see this Wiki. I will also point out the additional steps required to install the Google apps. Be aware that they will take up a lot of memory. You will probably not have enough space left for other (larger) apps. You can find the Google apps (‘gapps’) download on this Wiki page. Select the one for CM 10 (this will let you download ‘gapps-jb-20121011-signed.zip’).

And of course, doing this WILL WIPE YOUR PHONE. So  back up all your important data!

Find your IMEI code

You will need your IMEI code to get the unlock code for the phone’s bootloader. You can find this IMEI code in several ways:

• Open the Phone application on the Xperia Arc and enter *#06# to obtain the IMEI;
• On the device, go to in “Settings -> About Device -> Status”;
• Find the IMEI on the label on the box, if you still have it;
• The label inside your phone, behind the battery. It is printed next to the serial number (“S/N”).

I still had the box, so I found it there. It was in the format “XXXXXXXX-XXXXXX-X”.

Get the bootloader unlock code

To get the bootloader unlock code, visit http://developer.sonymobile.com/unlockbootloader/

1. Select your device and click the ‘continue’ button at the bottom of the page.
2. Enter your email address, agree to the terms and select ‘Submit’
3. Click the link from your email, enter your IMEI and continue
4. The unlock code should now appear, write this down for the next step.

Prepare your computer

Now you need to install the tools called Fastboot and ADB on your computer. On my Linux Mint it was as easy as typing:
sudo apt-get install android-tools-fastboot

sudo apt-get install android-tools-adb
If this doesn’t work for your Linux, or you are running some other OS, then consult the  Wiki or try The Easiest Way to Install Android’s ADB and Fastboot Tools on Any OS.

Prepare your phone

On your device, turn on USB debugging by going to Settings > Developer options and click to enable USB debugging.

As of Android Jelly Bean 4.2 the Developer options are hidden by default. To enable them tap on Settings > About Phone > Build Version multiple times. Then you will be able to access the Settings > Developer options.

Unlock the Xperia bootloader

First, put the phone into fastboot mode:

1. Power down device;
2. Plug data cable into PC;
3. While holding down the Menu button, plug the data cable into the device.

If successful, the LED will turn blue to indicate the device is in fastboot mode.

Then I typed “fastbood devices” to see if fastboot was working, but it responded with “no permissions fastboot”. So instead I tried:
sudo $(which fastboot) devices
which worked, it responded with:
BX902TBKQ2&ZLP fastboot
Then I unlocked the bootloader by typing:
sudo $(which fastboot) oem unlock 0x[YOURUNLOCKCODEHERE]
If this doesn’t work for you, you might instead try:
fastboot -i 0x0fce oem unlock 0x[YOURUNLOCKCODEHERE]
Of course, replace [YOURUNLOCKCODEHERE] with the code you got from Sony, and add the 0x in front.

Install ClockworkMod Recovery

Download the build package for your device that you’d like to install to your computer. I downloaded the file “cm-10-20131006-NIGHTLY-anzu.zip” which was the latest release, at the time of writing.

1. Extract boot.img from the zip to your computer, you will need this file for fastboot.
2. Put the phone into fastboot mode:
   1. Power down device
   2. Plug data cable into PC
   3. While holding down the Menu button, plug the data cable into the device
3. If successful, the LED will turn blue to indicate the device is in fastboot mode.

Open a terminal on the PC with admin rights, access the directory where fastboot is located, and enter the following:
fastboot flash boot boot.img

fastboot reboot
While the device reboots, press the Volume rockers a few times to load recovery.

Note: Once the device boots into ClockworkMod Recovery, use the physical volume buttons to move up and down. The home button is used to confirm your selection.

1. Select backup and restore to create a backup of your current ROM.
2. Select wipe data/factory reset. If you get an error formatting /data, try format /data and /data/media from the mounts and storage menu

Install the CyanogenMod ROM

Transferring and installing the installation zip packages using the ‘Sideload’ method:

Select install zip > install zip from sideload. Follow the on-screen notices to install the package by, on your PC type:

adb sideload cm-10-20131006-NIGHTLY-anzu.zip
If you want the Google apps, you should install them now:

Select install zip > install zip from sideload. Install Google apps, on your PC type:
adb sideload gapps-jb-20121011-signed.zip
The installer does not necessarily display an “Install complete.” message. You can tell the install is complete if there were no fatal error messages and you have regained control over the menu.

Select and execute wipe data/factory reset

Select and eExecute wipe cache partition

Once installation has finished, return to the main menu and select reboot system now. The device will now boot into CyanogenMod.