[Sony Xperia T, TL, TX, V] pfhastie:
Hi there

I am encountering an issue with my Sony Xperia T (FW: 9.1.A.1.141) which I am certain can be resolved with the correct tools and knowhow, but having spent the last week following what feels like every related link on the internet, I am no further forward - sleeping badly as a result - and very much in need of some help.

I'd prefer to avoid a torrent of potential fixes that I may already have tried at length so please forgive me if I go into too much detail. I just want to be very clear exactly where I am and what I have done so far to try and fix the issue. My PC is running Windows 7 64-bit (no issues).

This is my first proper smartphone so after a few months getting to grips with the underlying nature of the Android OS, I decided it was now time to root the phone and try out different ROMs etc. After reading what I could about the process, I finally used DooMLoRD's Easy Rooting Toolkit 17 (For Sony Xperia Devices) and was amazed by how easy it was to unroot my device. After installing Titanium Backup and fully backing up my files, I then installed ClockWorkMod Recovery 6.0.4.6 (For Sony Xperia Devices), and was able to boot into the recovery environment without issue (I also made an additional backup of the system at this point). So far, so good.

I then copied two ROMS to my SD card - Android 4.4.2 (KitKat) For Sony Xperia T (AOKP Build) & CyanogenMod 11.20140127 (Nightly) For Sony Xperia T - and tried to flash the CyanogenMod ROM from within the ClockWorkMod Recovery Environment, however I received a Status 7 Error, preventing me from flashing the ROM, then tried the same with Android 4.4.2 (KitKat) ROM, but again I received a Status 7 Error. As I attempted to leave the recovery environment to research the Status 7 Error, the program flashed a popup saying the phone was not rooted and would I like to root it. At this point, I assumed I had lost root as a result of the Status 7 Error, but didn't want to make any more changes, so chose no to the root option and restarted my Xperia T.

At this point the Sony logo went into a loop and despite restarting the phone using power and volume up many times, I was unable to boot back into the ClockWorkMod Recovery Environment nor connect the phone to my PC, although I could see the drivers appear for a few seconds in Windows before disappearing. It took me a good couple of days to realise that I had to fully charge my phone, so when I began the operation again with a fully charged phone I was able to update the driver in Device Manager from Sony Ericsson Seehcri Control Device (yellow exclamation mark) to Sony ADB Device (although the Sony Ericsson Seehcri Control Device with exclamation mark later returned so I am unable to assess how successful this actually was).

From here, I tried to update the phone using the already installed and up to date PC Companion, but the phone will not connect in flash mode, so it is not possible to connect the phone. I also tried the latest Sony Update Service (2.13.4.16), then Sony Emma Flash Tool (For Sony Xperia Devices), but none of these recognise the phone because I cannot get the phone into flash mode. Using the Android Flash Tool 0.9.13.0 (For Sony Xperia Devices), I am able to connect to the phone in fastboot mode, but when I try to install a stock kernel or any other variant, the Flash Tool states that I can't make any changes because the phone is not rooted.

Thinking I could root my phone again with DooMLoRD's Easy Rooting Toolkit 17, this time it no longer works, I assume because my phone cannot enter flash mode, even though it is recognised in Android Flash Tool 0.9.13.0 in fastboot mode (blue light).

Now, it is conceivable since my phone is no longer rooted that I may well be able to have my phone fixed under warranty and returned to me, however I would thereafter be scared to try and install a custom ROM, and would never really feel comfortable with the phone again, so I would much prefer to learn how to fix the problem myself. I am convinced the phone is salvageable because I have no issue recharging the phone, the screen is lighting up to display the Sony logo without issue and I am able to connect to my PC so that Sony ADB Device is recognised in Device Manager and via the Android Flash Tool 0.9.13.0, but can make no other changes.

My suspicion is that it has something to do with the ADB drivers, (which I linked to my Android Developer Tools Bundle 20131030 64-bit via the Windows Environment Variables), since no devices are recognised when I connect the phone and run the ADB Devices command in the Windows Command Prompt even when Windows is otherwise able to identify the device in Device Manager.

If anyone would be willing to talk me through this, I would be most grateful and would follow up all advice up so this information might be useful to others in the future as I can't see this being an isolated case. Likewise, if I am simply wasting my time and need to get the phone replaced or repaired, at least it would be good to know that I have exhausted all other options.

FYI Prior to the soft brick, I had USB debugging enabled and was in Mass Storage Mode (since this was more stable than Media Transfer Mode).