This needs formatting to make it easier to read. I will get around to it but here is the basic info needed!
Please READ this entire first post before asking questions that are already answered.
Today i have managed to flash the European Open Kitkat rom and root it and keep TWRP recovery. It worked for me but can't guarantee the same results for you.
Prerequisites. (Skip this if you already have rooted JB rom with custom recovery)
First i downgraded to Jellybean using this guide. I downgraded to "UK Open 16GB D80210B_00.kdz" i'm not sure if that's required though.
Then I rooted it using IORoot.
Then i installed TWRP using Freegee from the Play Store.
From here you are ready to flash or you can start from here if you already have root and recovery on Jellybean.
You need these three files.
1. My modded Stock rom zip.
Mirror 1 | Mirror 2
2. Savoca Modded Boot.img.
3. SuperSU ZIP.
Now to flash! (Take out your simcard first.)
1. Boot into TWRP and flash the modded stock rom DOWNLOAD 1. It will take a while and the screen may turn off during this, just press power button. Ignore the failed error!
2. Now go to main TWRP screen and select Reboot Recovery. (Wouldn't mount system otherwise!)
3. Now go to Mount and make sure System is ticked. (Not sure if required but do it anyway!)
4. Now flash Savoca's modified boot.img DOWNLOAD 2.
5. Again go to Mount and make sure System is selected.
6. Now flash SuperSU ZIP DOWNLOAD 3.
7. Now i wiped data here not sure if it's required as the rom wipes system but do it anyway!
8. Replace sim and reboot and all should be well!
Bugs and Fixes!
Audio Hissing/Crackling on Headphones.
This is present on all Kitkat roms currently. Some users don't get it most do. Type of headphones seems to be a factor. The following fix is temporary and will revert after a reboot. So needs to be repeated if your phones reboots for any reason.
Type in phone dial pad 3845#*802# and it will show Hidden Service Menu.
Click on "ELT Test", select "Manual Mode" and select "Test Start".
With headphones plugged in select "Audio Loopback" and than select "Test Start".
Blow gently into the microphone and keep on this test 20 seconds or more.
Once done back out and play music. Enjoy!
No LTE/4G anymore?
It seems to require a change of bands for some to get LTE working. There is a value to edit in build.prop. You can do this manually with a root explorer and setting correct permissions after changing, I've found the easiest way is to download JRummy Build.prop editor from market.
Open the Build Prop Editor app.
Find the value "ro.telephony.default_network" and select it.
Notice the property value will be set to "9". Change this to "11" and let the app reboot phone.
If you still don't have LTE try again but change the value to "13" and let the app reboot phone.
Bluetooth Battery Drain
This is NOT real battery drain so please don't worry about it. It is a falsely reported statistic. I get battery life on a par with 4.2.2. Around 8 hours screen on time which is fantastic! If you have battery drain please try a full wipe, don't restore apps from another rom do it manually. Take a look at your apps.
How is it done?!
The modded zip is stripped down to include only the System, Modem and Cust partitions. These are all that is required for Kitkat to play nice with Savocas modified boot.img. I edited the updater-script to remove the entries for all partitions except those listed above and repacked it up nicely to flash. So it is possible to do this with any future updates too. The Cust partition is necessary in case your partition has old carrier stuff still on there, this flashes a clean Cust partition.
LenAsh for the flashable zip i modded.
Savoca for the modded Boot.img and modules.
Chainfire for SuperSU.
Jesus for blessing all the little children.