It had stock 2.3.3, and it was unlocked following Alejandrissimo's method (http://forum.xda-developers.com/show....php?t=1254416)
Now it does not boot up, nothing happens if you press the on/off button
What do you advise me to do?
If possible I would like to put S.E.Tweaked rom v 0.7 and Inteks kernel v15 inside
So far I found this, should I follow first or second guide? Any other ideas?
1 Fota unbrick
Here is something to repair your bootloader after a FOTA update and phone iIn the package you have flash tool and the files you need.
Just unzip to a folder and then use flash tools.
The needed files are in the right folders.
After this you should have your phone fully back for a fresh rom install.
Use wotanserver to flash a full custom rom of your choice.
There´s not much to explain, this .sin and ftf files repair the damage bootloader and the trim area.
If you ´re unable to start phone after a fota update with unlocked bootloader.
Just plug the phone and connect it pressing back button in your xperia neo and press flash on the flashtool. And voila you have you phone live again.
2 [How-to] Repair Damaged Bootloader + Trim Area [Red Led][Unknown Device]
Sometimes we can brick our devices by a bad unlock, flashing process, or simply bad luck.
The phone doesn't turn on and there is a Red Led Of Death when pressing power button. Even with a GREEN led when we plug the phone with back key pressed the computer detect the phone as "unknown device" so there is no chance to get fixed by Flashtool or SEUS/PC Companion.
Well this problem normally means that the bootloader is broken or damaged. So, in order to fix it we need to write a new SEMCboot and after this we were able to flash a full and fresh firmware with flashtool and unbrick our Xperia.
This process like unlocking process requires SETool dongle/box and a paperclip to make a testpoint to put the phone in flash mode and be able to write the SEMCBoot.
I can help to anyone with a bricked Xperia Arc/Play/Neo/Pro just make send me a PM.