Hi
Short howto:
* install f2fs utils
pacman -S f2fs-tools
* create working directory
mkdir /root/raspbian
cd /root/raspbian
*Download and unzip your raspbian image
dd if=2017-04-10-raspbian-jessie-lite.img of=/dev/sdX bs=512k status=progress
* Put your SD-Card into your PI
* Let it setup everything
* install on your pi f2fs-tools
apt-get install f2fs-tools
* Shutdown your PI
* Insert your SD-Card to you PC
* Create directories
mkdir mnt
mkdir mnt/boot
mkdir mnt/root
mkdir boot
mkdir root
* mount raspbian SD-Card
mount /dev/sdX1 mnt/boot
mount /dev/sdX2 mnt/root
* make backup
rsync -av --numeric-ids mnt/boot/* boot/
rsync -av --numeric-ids mnt/root/* root/
* unmount raspbian SD-Card
umount mnt/boot
umount mnt/root
* recreate filesystems
mkfs.vfat /dev/sdX1
mkfs.f2fs /dev/sdX2
* mount raspbian SD-Card again
mount /dev/sdX1 mnt/boot
mount /dev/sdX2 mnt/root
* copy files to SD-Card
rsync -av --numeric-ids boot/* mnt/boot/
rsync -av --numeric-ids root/* mnt/root/
* edit cmdline.txt
sed -i 's/rootfstype=ext4/rootfstype=f2fs/' mnt/boot/cmdline.txt
* edit etc/fstab
sed -i 's/ext4/f2fs/' mnt/root/etc/fstab
* umount filesystemc
umount mnt/boot
umount mnt/root
Youre Done :-)
Have fun!