I finished and tested over weekend
Full rootable KitKat LG L7II P710 20a OPEN EU version KDZ.
Only thing i change is bootloader and recovery, to make it rootable.
Bootloader is well known zormax's work, and recovery is TWRP by christi9503.
All software from LG is included (and bloatware), stock odexed, clean, untouched.
Your data (contacts, messages, apps etc.), will stay untouched, but you can allways perform factory reset if you wish (RECOMMENDED).
UPDATED DOWNLOAD LINKS FOR MODELS IN POST#2
So, download firmware (P710CLEANMAXXV20A.kdz) from: https://www.dropbox.com/s/uhopxrcu3q...XV20A.kdz?dl=0
Or, if you want to try version 20C(TLF/TELEFONICA/SPAIN), i prepare that kdz, so you can download it from:
Download LG Flash tool 2014 from: http://www.mediafire.com/download/fw...+Tool+2014.zip
Unpck LG Flash tool 2014, place it on eg. c:\LGFlash tool 2014
downloaded firmware (P710CLEANMAXXV20A.kdz) must be in same folder with LG Flash tool.
Turn off device.
Press vol- and insert USB cable (to reach emergency mode)
Start LG Flash tool 2014
Select type 3GQCT
Version box dont touch (filed automaticaly)
Phone mode select EMERGENCY
Select KDZ file P710CLEANMAXXV20A.kdz
Press Normal flash
On next window press START
On next -RUN
On next -Clear phone software update Registry
Dont change Republic of Korea-english is default
Dont be scared when phone roboots on 95% of progress bar, i am, but it is (fortunately) normal.
download upgrade supersu from:https://app.box.com/s/212gq7b8jspgsgb6kfu6
copy upgrade supersu to external_SD
After downloading upgrades etc, turn off phone, and turn it on in recovery mode.
Flash upgrade supersu.
Here is KitKat 20a version for P713 CIS made by vvitaly
hacked bootloader from jb 4.1
minor kernel changes
And here is version 20a for P715 CIS (dual sim) made by vvitaly:
Special thanks goes to vvitaly from 4pda for help, guidance and patience.