Downgrade Z4 Tablet from .251

[jbresee]

Hi,

I accepted the upgrade to .251, and lost touchscreen responsiveness.  The tablet is now incredibly frustrating to use. It misses about 1/3 of screen touches.

Sony support suggested using the PC companion to recover the device.  This did a factory reset and reflash of .251, but the problem appears to be worse.

Sony support says that it is impossible to downgrade the Z4 but that's silly.  Do you guys have any thoughts on how I can revert to the release prior to the .251 release?

Thanks,

Jim

[Uliwooly]

@jbresee

You have 2 options

either you contact your local Xperia Care

http://support.sonymobile.com/global-en/contactUs/

or

use flashtool

/t5/Xperia-Z2/How-to-manually-update-downgrade-root-2014-Xperias/td-p/593459

[jbresee]

Thanks for the reply!

I've contacted support, and they say downgrading is not possible.

I looked at flashtool, and my concern is I can't find the ROM that precedes .251.  Does anyone know where I could find the previous ROM?

Thanks,

Jim

[Uliwooly]

@jbresee

Check the XDA forum.

[_alexdon_]

@jbresee There is a huge thread about downgrading here:

/t5/Software-Updates/Downgrade-Z3-compact-and-others-from-Lollipop-to-KitKat/m-p/955640#U955640

See the solution, you can use xperifirm.

[jbresee]

Thanks!

That's what I needed.

[_alexdon_]

Keep us updated.

[LiveWire07]

So I am thinking of trying this myself - however, I have never downgraded or rooted my product before.

My question is, if it is rooted (or in this case downgraded) will I be able to upgrade in the future on Sony's official released software/updates? Or will my device stay rooted?

[_alexdon_]

Downgrade is not equal to root. With downgrade you simply put an older firmware version. Warranty should also be intact. Updates will be received normally.

[LiveWire07]

I wanted to thank this team for the recommendation to downgrade - it solved my problem. As I assumed, the issue was with the .251 update.

I wanted to rollback to my stock version of the system software, but I was unaware of which version that was. Since I live in the U.S. my tablet was imported and I believe it came from Asia (specifically I want to say Hong Kong based on the service locations in the instruction manual).

Alas, Xperifirm did not have the older version of the software from the Hong Kong server, so I had to roll back using a version from Central Europe. Based on the region difference, I assume this will not cause an issue for the tablet?