1. Install the ROM Manager on your Xperia Z1 Compact. Get it from Google Play Store, then install the clockwork mod recovery.
2. Connect your Xperia Z1 Compact to your PC employing the USB information cable. Copy the “ROM.zip” file you downloaded to the SD memory card.
3. Restart your device in the recovery mode using ROM Manager. As soon as in Recovery Mode, go to ROM Manager and select backup / restore to back-up your information.
4. From the Recovery Menu do a total data erase (including Delvik Cache). When completed, go back to Recovery Principal Menu and choose Flash ROM from SD Card. Navigate the location you copied the ”ROM.zip” file and follow the directions for installing Android 4.4 KitKat on your Xperia Z1 Compact. As soon as the installation is over, just reboot your Xperia Z1 Compact device, and here you go, you’ve just upgraded it to the new Android 4.4 KitKat.