Mostly only devices with 16GB overall memory are hit by those "failed in buffer_write(fd))" errors because those have the smallest system partition.
Basically with the following commands we ensure that Kodi isn't installed into the system partition but "stashed" - which means its installed in the way bigger data partition like all normal appstore apps too. For this to work you need to install OpenSSH from cydia and connect to your device as root user via ssh (as mentioned everywhere, the default root password is "alpine")
In Cydia, add a new source with the url "https://clayfreeman.github.io/appstash/"
Install from cydia:
The following commands assume you are already logged in into your device via ssh (do ssh root@<ip of ios device> to do that from Terminal.app or putty or whatever ssh client you have at hand).
$ cd /var/root
$ wget <url to kodi ios deb>
$ dpkg -x <name of the downloaded kodi.deb> /var/root
$ appstash -a /var/root/Applications/Kodi.app/
$ rm -r /var/root/Applications
$ uicache; sync; killall -9 SpringBoard