Android 4.3 JellyBean is up and running now on the Nexus devices but the problem with it is that cell companies dona��t quite provide it immediately to its all models as soon as they have to work on a new overlay which they provide on their phones above the original Android. But in this case we need to thank the Cyanogen team for their hard work which has provided us with a working version of Android 4.3 optimized for the Sony Xperia Z1. This is not the officially released version, so please make a note of that. So if you wish to install this version on the Xperia Z1, then follow all the steps mentioned below and it will be done very easily.
Some Warnings to be noted:
First of all you need to remember that when you do this, you will be voiding the warranty of the phone. So you wona��t be viable for any free service from Sony. Secondly you need to make sure that you have a rooted device with unlocked bootloader and CWM Recovery or TWRP recovery installed on it. To avoid data clashes, backups are needed to be taken before continuing with the procedure.
First perform a NanDroid backup of your current ROM/Firmware. This can be done by selecting the backup/restore option on your recovery. This is highly recommended as you can restore your current ROM or firmware if anything goes wrong. Apart from this you also need to back up your messages, call logs, contacts and your apps. After all this do make sure that you note down your APN settings somewhere. These will come in handy later.
Make sure that USB debugging option on your phone has been turned on. If not then you can do this by following this path; Settings > About Phone > Developer options > USB Debugging. Make sure that all the drivers of the Z1 are installed on your computer and if not, then do install them before beginning. And finally always use original or good quality USB cables as you do not want them to falter in between. Also make sure your phone has a minimum of 90% charge so that it does not shut down in between the process.
Now before you start your process you will need to install the required files, so you get them from here.
Click on this link to download Fastboot and install on your computer. (http://developer.android.com/sdk/index.html#download)
Download the Xperia Z1 Cyanogen Mod 10.2 version zip file from here. (https://sites.google.com/site/projectfreexperia/download/cyanogen-mod-10-2) Finally the Google Apps package, you can get it from here. (http://goo.im/gapps/gapps-jb-20130813-signed.zip)
NOTE: Do not unzip the Cyanogen MOD and Google Apps package.
1. After downloading the above zip files, open the ROM zip file and extract the boot.img file to your desktop. Now connect your Xperia Z1 to the computer and move both the zip files from your computer to the devicea��s SD card storage. Make sure that the files are kept in the open and not in any folder.
2. Now disconnect your device and boot it into Fastboot mode by first turning your phone off and then on again by pressing a�?Volume Upa�?. While pressing volume up, connect your device to the computer via the USB cable.
3. Now launch Fastboot on your computer and select the Fastboot flash boot option and choose the boot.img file that you extracted earlier to the desktop.
4. After flashing the boot.img file, disconnect your Xperia Z1 and boot into your custom recovery mode by pressing Volume up + Home button + Power button. Now select clear cache, then dalvik cache under the advanced option. Go back to the recovery menu and select the data wipe-out option.
5. After the data wipe-out is complete, choose the Install option and select the Jelly Bean 4.3 CM 10.2 ROM file that you moved to your SD card storage earlier. After thata��s done, do the same for the Google Apps package by going to install option again.
6. Now go back to the recovery menu and hit the reboot option and you are done.
7. After you have selected to reboot, youa��re just a few minutes of reboot away from tasting the CyanogenMod ROM based on Jelly Bean 4.3 on your Sony Xperia Z1.
Do have some patience because the first boot usually takes quite some time. So do not panic if your phone does not start up for quite some time, but that should not be more than 15 minutes. If it is greater, means something has gone wrong and you might have to repeat the process to rectify it. Also this is an optimized version for the Sony Xperia Z1 and hence please do not use this on any other device as this will end up hampering the device. So enjoy the new Android 4.3 JellyBean experience and do let us know what you feel about it in the comments below.