This is an updated tutorial (as of Oct 2015) to root and upgrade the Japanese Sony Xperia A (SO-04E, Android 4.1.2 or 4.2.2) to Android 4.4.4 and then to Android 5. The Xperia A is the Japanese version of the globally released ZR. In terms of hardware there are two differences: the Xperia A has 32GB internal memory; and its NFC chip set is different from the one in the ZR - which is why NFC applications such as digital wallet (osaifu-keitai) will not work after going through the below steps. The Xperia A has a locked bootloader that cannot be unlocked.
I did not come up with the most important moves here. That was done by others in this thread and this one, notably aperception and mgg4000 (a big thanks to those two!). I only updated some steps that no longer work due to DoCoMo updating their firmware and closing the loopholes exploitable in earlier versions, files getting lost, software features changing etc. I also broke this down into more detail for people who are less familiar with the process of rooting and installing unauthorized ROMs. I have to warn that this will take an inexperienced person at least a few hours, possibly a full day. With complications arising, it could be more.
Also, you need an extra (external) microSD card in your phone for this to work. If you don't have one, you can buy one at convenience or electronics stores. Min 4GB should be fine but more is better considering future need for nandroid backups etc.
Anyway, here we go. In case a file linked to in the tutorial is missing, please see if it's among those I backed up in a Mega account, list at bottom of post.
1. Be sure you have an external SD card as per the comment in the above preamble. Note that at various points in the process the phone will ask you whether to install the Sony PC Companion link. Always skip this.
2. Write down all APN settings of your phone – you will need to manually enter them later.
3. Make sure your phone’s Developer Options are enabled, USB debugging is enabled, and Installing from Unknown Sources is enabled (google if you don’t know this stuff).
4. Install the minimal ADB and Fastboot tools from here: http://forum.xda-developers.com/show....php?t=2317790
5. Install Flashtool from here: http://www.flashtool.net/downloads.php . Watch this tutorial to do this and the next steps right: https://www.youtube.com/watch?v=ZfD9kT1DVz0
6. Power down your phone, hold down the Lower Volume key and connect phone to PC via USB cable. Flashtool will now show your phone as connected in Flashboot mode.
7. Using Flashtool, flash this to your phone: https://www.dropbox.com/s/p0m8fzv22m..._Hong_Kong.ftf
(or another C5503 Android 4.2.2 firmware – find one on XDA) . In the Flashtool settings, make sure you wipe the APPS_LOG and USERDATA
8. Disconnect and reboot.
9. You should now have a clean install of a Sony C5503 stock firmware. Confirm this in /Settings/About Phone.
10. If you check your Storage now, you will see only 4.59GB available internal memory, even though the Xperia A has 32GB total. To fix this, use Flashtool to flash back one part of the original SO-04E firmware here:
I used 10.3.1.B.2.13 which worked fine. When flashing this, you must wipe the APPS_LOG and USERDATA again, and exclude EVERYTHING except PARTITION. In other words, all items in the Exclude list must be checked, except PARTITION.
11. When this is done, reboot once more and check your storage again. You should now see ~25GB of usable internal space. Yay!
12. Now make sure you have wifi or phone network access. Wifi is easiest. For 4G/LTE you will need to manually enter the APN settings from Step 2 above first. Just one of them, the one you usually use is fine (in the case of DoCoMo, the most common one is moperaU)
13. Once your phone has mobile network (or wifi) access, go through the process of enabling Developer Options, USB Debugging and Installing from Unknown Sources again.
14. Log into the Google Playstore and install SuperSU
15. Now root your device with this: http://rootkitxperia.com/
16. Start SuperSU and set it up. Grant permissions as requested. If the installation is succesful, you have root.
17. Now install custom recovery. Get the latest dual recovery for ZR (installation file, not flashable file) from here: http://nut.xperia-files.com/). With the phone connected, run the English language install .bat
18. When done, power down device. Power it back up. As soon as the LED lights up (in other words, when the Sony logo appears) and until after you feel a brief vibration press any button on the phone repeatedly (e.g. the volume buttons) to enter recovery. The Recovery service will boot up.
At this point, if you haven’t yet, you need to familiarize yourself with Clockwork Recovery.
Wipe the cache partition, the dalvik cache (under Advanced), and wipe data/factory reset.
19. Reboot, connect USB cable and place the following file on your external SD card
20. Boot into Recovery, go to the Wipe options and Clean To Install New ROM. Then install the above file from the external SD card (the device has two SD cards, one external and one internal). This will install Android 4.4.4. Once done, choose the option to reboot the device. (When I did this the first time, Recovery warned that Root may be lost and asked whether to fix this. I chose “Yes, fix it” and rebooted. The good news was that Android 4.4.4 was installed correctly. The bad news was that Root was lost. WTH??? You may want to try NOT fixing it, see if that goes any better. The second time I went through these steps with someone else's Xperia A, this problem did not occur.) When the device has rebooted (and root was not lost), SuperSU should be present which means that you still have root. You can also double-check with an application called "Root Checker" from the Playstore. You may also want to check if Recovery is still on the phone and working (by rebooting the phone and pressing the volume keys when the Sony logo appears.) If Recovery is no longer present, go back to step 17 and repeat. Then come back here. If you have both root and Recovery, you can now skip to step 22.
[21. ONLY if you have lost root like I did, follow these instructions to regain Root (the root kit from step 15 will no longer work on this new version you now have; you can use the Flashtool we installed in step 5, no need to download the official Sony one)
After flashing the two firmwares and rebooting, each time a “repairs in progress” type of screen appeared and shortly thereafter the phone seemed to power down. I had to remove the battery each time to get the thing started again. Also, while on the Nordic firmware, the phone kept vibrating for no reason. This problem disappears when flashing back the second firmware from the above instructions.]
22. You now have a rooted Android 4.4.4. Presumably you will want to move on to the very latest Android version which is Android 5.1.1. Keep in mind that the Xperia A has a locked bootloader so only ROMs that are designed for a LB will work. I installed this one, works perfectly except for NFC:
That’s it. Unfortunately, links included in this tutorial are liable to go dead after a while. Here are the ones likely to vanish, duplicated in a Mega account I set up for this.
Step 7: C5503 HK firmware (C5503_10.3.1.A.2.67_Hong_Kong.ftf):
Step 10: SO-04E firmware (10.3.1.B.2.13):
Step 19: Pre-rooted 4.3.3 (C5503_10.5.1.A.0.283_NCB_PRE-ROOTED_PRFCreator.zip):
Step 21: Nordic firmware (C5503_10.5.A.0.230_Nordic NCB.ftf):
Step 21: C5503 Kitkat (C5503_10.5.1.A.0.292_RU.ftf):