why Xperia U restart all the time

[arch9804]

Why my Xperia U restarting over and over again with some kind of flash I don't know what is that. Someone help me please! It stuck at Xperia logo followed by some kind of flash on the screen.

[MarlonUk1]

it is called a bootloop.
where you trying to flash it with a custom rom?

try to repair it using http://support.sonymobile.com/gb/tools/pc-companion/ (assuming you did not unlock bootloader)

If you tried it flashing with custom rom, try to do the process again,

[Christofer]

Hi @arch9804,

You can try removing the battery in your Xperia U to stop this. However, if the same thing starts again when you put the battery back in and power on the phone you should try performing a software repair using PC Companion as nolramlb suggested.

[arch9804]

I have tried it many times using pc companion but unfortunately my laptop cannot detect the device. Disconnected show up.

[Christofer]

Do you get as far as step 10 in the software repair guide (http://talk.sonymobile.com/t5/FAQ/How-to-perform-a-software-repair/m-p/1061294) before you are unable to proceed?

[arch9804]

The link is invalid. Unable to proceed. 

[_alexdon_]

@arch9804 The link should be ok now.

[Christofer]

@alexdon Thanks for the edit.

[collins4711]

Hi Chistofer, 

I am also having a problem with boot loop, I have also tried using the Companion Software Repair but it stoped and says software  error, contact Sony support.

zorro4711

[Uliwooly]

@zorro4711

Do you experience the same without the SIM and SD cards?