I have compiled a CLEAN completely unmodified FTF for C6902.
Yes, it does include all original system languages, as this is the Stock Firmware.
When you install, allow ~5 minutes for first boot to fully install.
For Recovery & Root:
- Boot in flashmode and flash either of these images #1 or #2 (The one I used)
--For #1 use the command
fastboot flash recovery twrp-z1-2860.img
--For #2 use the command
fastboot flash boot boot.img
- Boot into Recovery and wipe cache/dalvik (recommended but optional), and flash SuperSU zip file.
- Do NOT reboot, and then flash [NUT]'s XZDRecovery Flashable ZIP Z1-lockeddualrecovery2.8.12-RELEASE.flashable.zip
- Now reboot, and enjoy root! (Rhyme unintended)