debianxfce

Armbian uses old kernels. The build process starts with the ../compile.sh file.  Packages to install is defined in the configuration.sh file.  Additional files are written in the distributions.sh file.

You need to create whole image when developing a kernel,  because of the separate FAT partition that does not support symbolic linking to your new kernel but when creating an image you can use symbolic linking. How to make an image, use the command
git clone -b some_branch some_armbian_repository
and study the image creation scripts in the lib directory. Armbian installer scripts do have some documentation too, but it is better to learn to edit the scripts for your liking.
After cloning balbes150 git, you can copy my edited lib files over the armbian lib files and create an image:
xfce@carrizo:~/Downloads/arm$ ./compile.sh BOARD=amlogic-s912 PROGRESS_DISPLAY=plain RELEASE=testing PROGRESS_LOG_TO_FILE=yes KERNEL_ONLY=no BUILD_DESKTOP=yes BRANCH=next CLEAN_LEVEL=debs NO_APT_CACHER=yes
 

Product specs does not list Linux support so maybe there is no driver in the Linux kernel.

To test the mainline kernel 4.13, you can use my image:
https://www.youtube.com/watch?v=ujnYBvMQfjM
 

Put your kernel tree under sources/LINUX_NEXT.  For example you have  linux-4.13-rc1 directory there. Then I have  in the /lib/config/sources/amlogic-s912.conf file:
next)
    KERNEL_USE_GCC='> 6.2'
    KERNELSOURCE=''
    KERNELBRANCH='branch:linux-4.13-rc1'
    KERNELDIR='LINUX_NEXT'
    SCR_BOOT='boot-amlogics905x_AM.cmd'
 
Then start image making:
./compile.sh BOARD=amlogic-s912 PROGRESS_DISPLAY=plain RELEASE=testing PROGRESS_LOG_TO_FILE=yes KERNEL_ONLY=no BUILD_DESKTOP=yes BRANCH=next CLEAN_LEVEL=debs NO_APT_CACHER=yes
 
 
RELEASE=testing means Debian testing Xfce. I have modified image making scripts for that

You can try my image, see: https://www.youtube.com/watch?v=UsNzZn-luc0

You should change PART_ROOT="/dev/mmcblk0" . These I am not sure but I would try to  replace /dev/boot to /dev/mmcblk0boot0 and /dev/dtb to /dev/mmcblk0boot1. Try to mount them and inspect the content.   Or I am totally wrong, google and try yourself. I feel that it is a bad idea to use the emmc partition. Resale will be easier in a original condition and dual boot android/linux is a bonus. There is no accelerated Linux gpu driver for S912 but android does have.
 
The script copies folder by folder to the emmc, so a  64 GB sdcard is not a problem if the card works fine with ext4. Mine chinese 7 usd class 10 64 GB card does have reading errors and got money back from a ebay shop. I use my Samsung Evo 32GB class 10 card happily with Sunvell T95Z Plus.
 

gparted does have a graphical user interface when you run that in a Linux PC. You must run that as root. Expand the partition with the mouse.

Add the line to /etc/modules:
wifi_dummy
 
Upgrade to Debian testing and install Wicd and remove networkmanager and systemd networking.service. Install correct firmware to /lib/firmware, use dmesg to see if firmware is missing  This is solution for Sunvell T95Z Plus Amlogic S912. Resolution can depend on the monitor, so there is no compatible resolution.

I just added that and your post came before I clicked  Save.