Convert a TWRP Backup Ext to a F2FS compatible Format (Android 5.1.1) ?

Hi,
I use a Stock 5.1.1 Android Rom on my S6 Edge LDU with some selfmade modifications (Debloat, Kernel Upgrades etc.).

Flashed a new Kernel (F2FS compatible) but my Rom seem's to be not compatible with F2FS because it get's always stuck on Boot Loop.

I tryed the following way:

I created a Flashable Zip -> http://forum.xda-developers.com/show....php?t=2746044

And converted it to F2FS but i always get the Device not Compatible error -> http://forum.xda-developers.com/gala...t2840303/page2

Is there anyway to Convert my TWRP Backup to a F2FS compatible format ?

Thanks