I had the same problem that I managed to solve thanks to this:
However, there are small changes to be made.
You have to read the link first to understand and then do the following.
At home it looks like this:
Connect with PUTTY:
killall -9 xbmc.bin
systemctl stop kodi.service
mkpart primary 1081344s -1
e2fsck -f /dev/rknand0p2
mount /dev/rknand0p2 /storage
systemctl start kodi.service
Sometimes there are a few mistakes but you have to go all the way.
In any case with me it works perfectly.
I hope it will help you.
Thanks for the write up, but this did not work for me. I tried to follow the commands and some did not work.