** THIS WORKED ON MY DEVICE BUT IT MAY NOT WORK ON YOURS. APPLY AT YOUR OWN RISK **
This has been tested with the Italian firmware released on 4/30/2015, PDA: P905XXUABOD7, CSC: P905ITVABOD7 (of course the language can be set to English after installation). This method should however work for other Lollipop releases as they become available in your region. This method does not trip the knox flag.
1- Rooted KitKat (the easiest way to get root is to flash a ROM dated before June 2014 and root it with Towelroot).
2- FlashFire app v 0.17 or higher: The only way to get it is by following the instructions at: http://forum.xda-developers.com/gene...hfire-t3075433
1- Make a back up of all your files.
2- Download your Lollipop ROM from Sammobile and unzip the .zip file to get the tar.md5 file. Copy the tar.md5 file to your sdcard.
3- Run FlashFire. Tap the +, Flash Firmware Package, and select the tar.md5 file. It will scan the file and opens a menu of option to choose.
4- Choose: Boot, Recovery, System, Cache, Preloaded/Hidden.
The rest should be unchecked. Now tap the check mark at the top right corner of the dialog box.
5- When that is done, FlashFire adds two items to the list of actions: Process Cache and EverRoot. Open process cache and uncheck all the items. Open EverRoot and select Inject SuperSU and unckeck the other options.
6- Tap the + again and choose Wipe. Select System, Dalvik, and Cache. I highly recommend that you check 3rd party apps too, which will erase your existing apps and settings but it will give you a clean install. Do not select Internal storage unless you want your internal SD card erased too.
7- Tap and hold to move the boxes containing the actions to get them in this order: Wipe, Flash Firmware Package, followed by the rest.
8- Tap the Reboot box and select Reboot to Recovery.
9- Hit the FLASH sign at the bottom of the page and hit OK. THE SCREEN WILL GO COMPLETELY BLANK DURING THE FLASHING OPERATION. Do not freak out. This is a bug in the tool and will hopefully be fixed in a future version. After 5-10 minutes your tablet reboots. If it takes longer than 20 minutes something is wrong.
10- During the first reboot it may take 5-10 minutes before you get the initial setup dialog. (If it takes longer than 20 minutes something is wrong.) Complete it and you will be on rooted Lollipop.
TiP: Settings -> General -> Security -> Security Policy Updates -> Uncheck Automatic Updates, and also Settings -> General -> About Device -> Software Updates -> Uncheck Auto Updates
If after the upgrade you suspect something does not work, install Flashfire on your rooted lollipop and start from step 4 again.
If you are not happy with the results, or something goes wrong, download a KitKat firmware from Sammobile and flash it in ODIN. Make sure to clean cache and data in recovery.