[Xperia Z1 General] joedeveloper:
When I saw that I could upgrade to Lollipop I was interested. Then I realized there probably was no root for this yet. So I went about figuring out a way to root it before going to it. Technically this isn't a root once you have already gone to Lollipop.

THIS WILL ONLY WORK IF YOU ARE STILL ON KITKAT, ROOTED, WITH RECOVERY (TWRP is what I use via NUT's Dual Recovery for the Z1).

Requirements:

PRFCreator - Creates pre-rooted firmware - Click Here to Download

Flashtool - Allows you to flash the FTF - Click Here to Download

The FTF for the upgrade - C6916_14.5.B.0.236_T-mobile_US.ftf - Click Here

The latest SuperSU zip from ChainFire - Click here to Download

I'm assuming you have adb, drivers installed and a general understanding of how to navigate the tools above, if not read up on how they work.

Create a pre-rooted flashable firmware with PRFCreator. Install/Download PRFCreator and put the FTF and the latest SuperSU binary zip in the spot labeled SuperSU Zip. Make sure to check the box next to kernel in the include box on the top right side. See screenshot below.

[IMG="PRFCreator"]http://i.imgur.com/xzr091q.png[/IMG]

Congrats you have just created a flashable zip with SuperSU loaded into it. You might ask why you're not gonna add NUT's XZDualRecovery into there. Reading on the forms at the time of this post and it apppears that PRFCreator and/or Nut's recovery doesn't play well with Lollipop and causes bootloops. So run NUT's Z1xzdualrecorvery installer via bat or sh after the fact and not during via PRFCreator until they can work it out.

Make sure you have the original C6916_14.5.B.0.236_T-mobile_US.ftf in the firmwares folder either C:\Flashtool\Firmwares or C:\User\[username]\.flashtool\firmwares

Now take the flashable zip you created via PRFCreator and put it on your phones internal storage, sdcard etc.

Now that you have the flashable zip with SU preinstalled and ready to fire, reboot your phone into recovery. adb reboot recovery etc.

Once your phone has rebooted into recovery you will need to flash the flashable zip you created with PRFCreator.

After flashing the zip I'd suggest wiping the cache/dalvik. And then you will want to go to the reboot screen and power off the device.

Once the device is powered off open Flashtool.

After it loads and syncs the devices (takes a second) you'll want to double click C9XX from the list (Z1).

Next click the BOLT icon in the top left navigation that has a tooltip that says "Flash"

When the flash screen comes up select the right firmware based on the FTF location, check SYSTEM and BASEBAND under the exclude section and uncheck DATA under the wipe section, I unchecked APPSLOG but you don't have to uncheck it (to be honest I think it slowed my initial bootup by upgrading my apps) via this screenshot:

[IMG="FlashTool Screen"]http://i.imgur.com/tsknFvM.png[/IMG]

Now click the "Flash" button with your device disconnected and powered off. Follow the directions. For your Z1s you'll want to hold the "DOWN VOLUME" button and then plug the USB connector into it.

Next you will see Flashtool flashing away. Once it's complete you can unplug your phone and then power it up.

Your device is now rooted and running Lollipop. In terms of installing a custom recovery, again all of that is untested and you'll need to play around with the latest XZdualrecovery from NUT to see how it works.

REMINDER: This doesn't solve killing ric etc. Which is important to note for being able to mount the system etc. You can kill ric via tasker and an .sh script like I do or via a flashable kill ric (seen a few floating around) if you get recovery installed after the fact etc.

Thanks to:

Chainfire for his SUPERSU

zxz0O0 for his PRFCreator tool

Androxyde for keeping flashtool going

greatremix for posting up the FTF

I'll be uploading the flashable zip that I made from PRFCreator. It's over a gb obviously so it might be just as easy for you all to create it yourself.