I had this issue after upgrading to Krypton as well. It would get past the system boot and then just sit at a blank screen. I assume it had something to do with kodi-openbox so I did the below from my original setup to correct. After I ran the following steps it worked after reboot and the plugin upgrade completed and Krypton was usable. These are just steps taken from Solberos minimal install guide (section 5.2 - excellent guide if you have time to read through) for Jarvis 16.1 on Ubuntu 16.04.
either ssh to your kodi box or open a terminal by pressing CRT-ALT-F1
To install kodi-openbox Xsession, download the latest .zip file from the GitHub master branch. The file is named “openbox-kodi-master.zip” by the below code.
wget -O openbox-kodi-master.zip
https://github.com/lufinkey/kodi-openbox...master.zip
Extract the .zip file.
Code:
unzip openbox-master.zip
If you get a prompt telling you are missing the package unzip, install it.
Code:
sudo apt-get install unzip
Move into the extracted directory, create a .deb package from the extracted content and install the .deb.
Code:
cd kodi-openbox-master
bash ./build.sh
sudo dpkg -i kodi-openbox.deb
reboot
Hopes this helps, it fixed it for me.
FYI - The ppa has been updating the packages rather quickly but they were trickling out over the last 36 hours. You may want to do an apt update and then an apt dist-upgrade and see if any additional packages were not out there when you first performed the upgrade.