What and how to update your device if your bootloader is unlocked

Why can't I have OTA or Xperia Companion Updates?
Because your bootloader is unlocked you lose the feature of recieving OTA updates or Xperia Companion updates.

What do I do if I want them back?
Now here it gets a bit tricky, how? well when you unlock your bootloader you lose a thing called DRM Keys, I'm not going to get in much detail about what are they but I will say that they are responsible for the OTA or Xperia Companion updates, and that's why when you unlock your bootloader you should ALWAYS backup your DRM Keys (search here on xda for tutorials). Now, if you didn't back your DRM Keys then you're basically out of luck on recieveng OTA Updates but there is a way in which you can get updates, I will discuss about this later on this thread. But if you did back your DRM Keys there is a way of restoring them, meaning you can recieve your OTA Updates again. If you haven't backed up your DRM Keys please follow this thred to see how to manually update.

Before we begin
Make sure you have the following:

1. A Windows Machine (32/64 bit)


2. An Internet Connection


3. Time depending on your internet speed


4. And patience

Let's Go!
I will keep this in simple steps for easier understanding.

1. Download Flashtool from here:https://www.androidfilehost.com/?fid=24459283995311021


2. Install Flashtool


3. Go to the folder where you have installed Flashtool and go to the Drivers folder


4. Launch Flashtool drivers and from the menu select FLASHMODE drivers


5. After the installation is finished, launch Flashtool and wait for the syncing to finish


6. Download the firmware you want for your device using XperiFirm(you will see the icon in Flashtool)


7. After the downloading is finished, press on the lighting icon and select flashmode


8. Navigate to the folder in which you have downloaded your firmware


9. DO NOT untick anything on the right side of the program


10. Power off your phone (make sure you did a backup of your data as everything is going to be wiped)


11. Press the POWER BUTTON + VOLUME DOWN button until you see the LED notification light turn to green


12. Wait for Flashtool to tell you to connect your phone


13. If you did everything correct you should now see that the firmware started to flash


14. DO NOT unplug your device until you are proceeded to

Advice
If you do think about unlocking your bootloader, please back up your DRM Keys.

Hit thanks if it helped!