[Xperia Z5 Q&A, Help & Troubleshooting] koekoek91:
[MENTION=8103901]Spawnos[/MENTION] [MENTION=6152918]tashum[/MENTION]

Alright guys, I will (TRY) to help you with some of my experiences.

I have bricked my phone like this a couple of times before, just like in your case I only had a red blinking or constant red led.

The only difference is that for me this didn't just happen after an OTA update, but it was my own mistake for messing up my phone.... but the end problem seems to be the same as you guys have.

First I want to ask, because I think it hasn't been asked or mentioned ( I am sorry if I missed it, just quickly read through the thread).... are the fastboot and flashmode drivers installed correctly aswell?

What Windows versions are you running?

On windows 10 for instance I know there is an additional step where you need to start in advanced startup the PC to be able to install the flashmode driver correctly.

You have to disable driver signature verification ( or what its called) on Windows 10... that much I know since I am a Windows 10 user myself.

Maybe I have always been lucky, this could be why I still have the same Z5 working again today.... but what I did (after making sure all drivers we're installed correctly),

was to just don't give up and keep playing with the phone in combination with Flashtool.... eventually when holding volume down and plugging I would finally get the green indicating flashmode.

What I have found best to do is make sure you have an FTF ready to flash:

IMPORTANT: leave your phone unplugged and completely turned off first, BEFORE doing these steps:

1. Click on the lightning icon and choose flashmode...

2. Choose your firmware...

3. Check every box under wipe. Yes this will wipe everything on the internal storage ( its a bummer I know, but I think you have bigger problems to worry about)...

4. Click flash and let the files prepare for flashing...

5. Once the files are prepared, another window will pop up telling you Flashtool is waiting for phone to be connected in flashmode....

6. Make sure that your phone is completely turned off before plugging it to your PC (Volume button UP + power button should turn it off... wait till you feel three vibration)...

7. Then its time to start pressing volume DOWN button and plug it to PC...

If nothing happens or you just get the red led blinking again, retry starting from step 6.

IMPORTANT: I have found (in my cases) that it was extremely important to have the FTF flashing process prepared BEFORE starting to try to plug to PC while holding volume DOWN button,

because when having the flash process prepared before plugging your phone to PC it can immediatly start the flashing process even if its just a millisecond that you're getting a tiny little green light.

Additionally if the above didn't work ( make sure you don't give up too easy on it :p).....

You can try taping your volume UP button + the power button (while they are both pressed in) for about atleast 8-12 hours ( to get the battery completely discharged) and then try the above flashtool steps again.

I have never had to do this taping step myself before, but I have heard stories where it worked.

I don't know if any of this will work for you guys, but I just felt like I needed to share some of my experience about this with you :)

I wish you guys good luck, patience.... and keeping my fingers crossed :fingers-crossed: