Help Downgrading your Android version ?

[Smirnoff103]

Hello,

I have a Xperia ST25i (or Xperia U) and I experienced an issue with my contacts that my phone couldn't start the application anymore to view my contacts, very annoying indeed.
So I updated my phone, and got a new Android version with it, but since then my phone is INCREDIBLE slow. It takes ages to open my messages / contacts / picking up a call..., probably because the Android version I have now (4.0.4) is too heavy for my phone.

So my question is: can I downgrade my phone to the older version of Android I had when I bought my phone (if I may believe Wiki the 2.3.7 version) ? And if yes how ?
I tried the factory reset with the Sony PC Compagnon thing but it didn't helped anything.

Thanks for your help.

Regards from Belgium

 

[Mr. Lucky]

Factory reset only resets it to factory condition (i.e., no user apps) at the currently installed OS version. It won't downgrade to the Android version originally loaded from the factory.

Moving to Xperia U forum for (hopefully) specific advice from others with this phone.