ZU downgrade query - Sony Xperia Z Ultra

Dear experts, I bought this phone recently and it came with 5.0.2, 14.5.A.0.270. I have rooted my phone and flashed dual recovery and have TA backup. bootloader is locked.
I want to flash 4.4.4 as I don't like lollipop. Can I just flash C6802_14.2.A.0.290_Customised IN.ftf.
Please help. Thanks.
Sent from my C6802 using Tapatalk

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If I remember this right radio will not work. Follow guide here
http://forum.xda-developers.com/showthread.php?t=2593918
READ THIS: BACKUP INTERNAL STORAGE TO YOUR COMPUTER. REMOVE EXTERNAL SD CARD!!!
ALL STORAGE WILL BE WIPED!​
I have done this a very long time ago, many times. Bare with me...I might not remember everything.
Follow this
Downgrade path 1 (very easy):
Download needed files
Download C6833_14.1.B.1.532_NUT.ftf
Flashing using flashtool
Flash EVERYTHING in the above ftf by @[NUT]
Reboot
Flash EVERYTHING in this ftf, (use the defaults) it will do the downgrade below so you will end up on .532 with a working IMEI ready to root with bin4ry's tool
http://forum.xda-developers.com/devd...ct/dl/?id=3442
You will end up with a device that thinks it is a C6833 but when you flash 4.3 or newer (.290 or .136) just use the one for your real model and the model number will be restored.
Click to expand...
Click to collapse
source: http://forum.xda-developers.com/showthread.php?t=2593918
When the above is done choose a kitkat stock .ftf rom to flash. Choose an .ftf file to flash that matches your model: C6802,C6806, C6833, C6843, or SOL24.
Look here
http://forum.xda-developers.com/showthread.php?t=2453921
or here
http://forum.xda-developers.com/xpe...tf-depository-sony-firmware-releases-t2829387
I do not know which stock firmware is based on what android version. You have to look this up yourself.
I never used stock roms more than a month or so when first I bought my device. This was two years ago.
I will take a guess that 14.4.A.0.108 will be your choice of stock rom which is based on 4.4.4.
I do not know if there are any more recent stock roms that is based on kitkat or if they jumped to lollipop after this.
Notice: .118 is only a special release from carrier like vodaphone and some french carrier. So no need to download this firmware.

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Thank you very much sir. I shall follow the links and your detailed tutorial and post back the results.
Sent from my C6802 using Tapatalk

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Rollback to 4.4
Hello,
I did the rollback yesterday as I couldn't bear Lollipop's bugs, slowdowns and so on...
All you have to do is to find a 14.4.A.0.108 firmware using XperiFirm which is included in Flashtool.
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Or download the one you need here: http://forum.xda-developers.com/showthread.php?t=2453921
"Generic" firmwares are the ones to use if you have an unbranded phone (that is to say, not sold by a carrier).
Then you can follow this tutorial almost to the letter here: http://www.xperiablog.net/2015/03/1...xperia-lollipop-using-xperifirm-and-flashtool
Please post again if you have further questions.

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Guerrick said:
Hello,
I did the rollback yesterday as I couldn't bear Lollipop's bugs, slowdowns and so on...
All you have to do is to find a 14.4.A.0.108 firmware using XperiFirm which is included in Flashtool.
Or download the one you need here: http://forum.xda-developers.com/showthread.php?t=2453921
"Generic" firmwares are the ones to use if you have an unbranded phone (that is to say, not sold by a carrier).
Then you can follow this very tutorial almost to the letter here: http://www.xperiablog.net/2015/03/1...xperia-lollipop-using-xperifirm-and-flashtool
Please post again if you have further questions.
Click to expand...
Click to collapse
XperiFirm, I have never seen this feature before. It must be new? Smart!
I don't use flashtool that often anyways..

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SÜPERUSER said:
XperiFirm, I have never seen this feature before. It must be new? Smart!
I don't use flashtool that often anyways..
Click to expand...
Click to collapse
Indeed, both were separated before, but then one of the devs thought it would be more convenient to get the two programs together in Flashtool.
Moreover, you don't need to create the FTF file yourself when you download through the XperiFirm included in Flashtool, Flashtool does it automatically if I remember well, avoiding the hassle to delete the "fwinfo" file that corrupts the FTF file when you create it on your own.