[Q] Please help me rooting a branded G900F topic

Howdy y´all ,
I´ve been trying to figure out for the entire day how to root my G900F with stock FXXU1ANI3 firmware ( Vodafone Germany branded) . Unfortunately the build date is Sep 12 2014, so I can´t just flash the latest german unbranded version with KIES. Everyone is telling me that I should root first and backup EFS partition before using Odin, so I don´t just wanna flash CWM, trigger Knox and flash a rom . And I can´t just follow the towelroot guides because the stock kernel is nowhere on the Internet.
Can someone give me some advice what I can do to gain root access? I just need to change SELinux to permissive and install Appradio Unchained to pair with my head unit.....

Thanks in advance :)

(holy cow, rooting has become so complicated....I was 14 when i got my first Galaxy in 2010, hence my stupid username here and rooting was so easy back then....)

[Q] Can I flash g900f lp roms for my g900t？ topic

Will I get troubles？

G900F generalized lag topic

Good day everyone. I came from the Note 3 N9005. Just can't help but notice the S5's generalized lag. Lag is everywhere. Almost all the apps I used to use on my Note 3 smoothly, lags here.
All apps stutter specially when scrolling quickly, which I didn't get on my Note 3. Tried restoring several times to no avail.
Is there any way to reduce the lag? Will flashing the Poland Lollipop firmware solve this?
I dont want to root or anything, and void my warranty, so everything, i like to stay stock as what i did with my Note 3 without any problems.
Any suggestion would be greatly appreciated.

Any suggestions about G900F lag? topic

Good day everyone. I came from the Note 3 N9005. Just can't help but notice the S5's generalized lag. Lag is everywhere. Almost all the apps I used to use on my Note 3 smoothly, lags here.
All apps stutter specially when scrolling quickly, which I didn't get on my Note 3. Tried restoring several times to no avail.
Is there any way to reduce the lag? Will flashing the Poland Lollipop firmware solve this?
I dont want to root or anything, and void my warranty, so everything, i like to stay stock as what i did with my Note 3 without any problems.
Any suggestion would be greatly appreciated.