The Android 4.4 KitKat firmware has caused a lot of controversy since it was first released. As expected, Google tried to offer a new perspective regarding the operating system and, in this respect, KitKat OS brings multiple improvements, changes, and options. However, such a change is more than expected, but it is still unavailable for most Android devices out there.

For this reason, many developers are working quite hard in order to bring the well-awaited firmware to many other smartphones and tablets on the market. As you can imagine, for older devices, the Android 4.4 KitKat is merely a dream since most of those low-end devices do not support the firmware. In this case, the only solution remaining is to install a custom ROM,  firmware that replaces the Android firmware, but it still brings the same features and capabilities.

If you happen to own a Sony Xperia Z1 and you want to be able to run Android 4.4 on it, find out that there is hope. You can easily install the SlimKat Android 4.4 firmware on Sony Xperia Z1 as long as you follow the instructions explained bellow. In the same time, it is worth mentioning that this Custom ROM prevents Flashlight from working. I am sure that developers will fix this problem, but if you do not mind of not using the flashlight, but instead to use Android KitKat, then you are good to go.

Moreover, I want to remind you that once you install an alternative Custom ROM on your Xperia device, your warranty will be voided. As a different matter, if something goes wrong during the process, you will be the only responsible if you lose all your data. Therefore, keep in mind to follow each step as indicated.

Preparatory Steps

1. Check the model number to see if your device is eligible to run the SlimKat Android 4.4 firmware. The build number has to be C6902/L39h/C6903/C6906. Any other device is not compatible with the process.
2. Charge your device at least with 50% battery. This is a battery-consuming process, and if you happen to run out of battery life, you might lose some important data, and you can even damage your smartphone.
3. Backup your device to protect your personal data. Apps, data apps and other personal files might be deleted during the process, and if you want to be able to use them later, you should start a backup process.
4. In the same time, you need to install the latest driver. You must have a proper and working driver installed on your computer in order to flash the kernel successfully on your Xperia Z1.
5. Unlock Bootloader before you proceed with the steps suggested bellow. Without unlocking the Bootloader, you will not be able to use the fast boot commands to flash the Custom ROM.

Required Downloads

You need to prepare all the files before you start the process. In this way, everything will be set for the installation procedure. However, keep in mind to flash the ROM file first and then the GAPPS file. In the same time, transfer both files into a separate folder on your phone.

• Download SlimKit Android 4.4 ROM (243 MB) from here
• Download GAAPS file (54.63 MB) from here
• Download FASTBOOT file (11MB) file from here

Install SlimKat Android 4.4 Firmware on Sony Xperia Z1 (CWM Recovery Guide)

1. Extract Fastboot file and Rom file into a separate folder on your computer. At this point, copy the boot.img file to the folder where you have placed the Fastboot file.

2. Boot into Fastboot mode and flash the ROM file (boot.img file). For this, you need to power off your device first. Press and hold the Volume Up and connect your device to the computer using the USB cable. This should turn the LED blue.

3. Once the fastboot mode is launched, navigate where you have extracted the fastboot file and, while holding down the SHIFT and Right CLICK select “Open command window here”.

4. Flash the boot.img from the command prompt. Search for “fastboot flash boot boot.img” and type it down into the command prompt box.

5. Enter Recovery mode from fastboot directly by tapping/pasting the “fastboot reboot” command into the command box. Now, your device will reboot. It is important to unplug the USB cable once you see the Sony logo. You will be notified through a Purple LED light to press the Volume Up button 2-3 times to reboot into recovery mode.

6. Create a Nandroid Backup from recovery. It is not mandatory, but it is very important to do so if you want to prevent other problems. For this, just go to Backup and Restore and select Backup.

7. In the same time, it is advised to run a full clean up of the device. As for the record, this will delete all your apps and settings. For this step, you will have to go to Wipe data/Factory reset and then to select Yes on the next screen that will appear. In the same time, you will have to choose Wipe Cache Partition and select Yes. Next select Advanced and choose Wipe Dalvik Cache. Again, select Yes in order to confirm and save changes.

8. Install the Custom ROM file. For this, go to Install Zip, and then select Choose Zip from SDcard. Now it is a good time to remember where you have saved the downloaded files.

9. Flash the GAPPS file in the same way as you did with the ROM file.

10. Reboot your device from the recovery menu where you select reboot system now.

This is the whole process. Now your tiny Sony Xperia Z1 should have Android 4.4 Firmware installed with the help of SlimKat Custom ROM. If you happen to encounter any problems during the process such as stuck at logo, feel free to redo a factory reset, and you can repeat the process.