I’ve tried to install the new Jarvis testbuild but it terminated due to EXT4-FS errors. This happened on both SD cards that I used to upgrade to OSMC 2015.12-1. After reading the issues with the new SDHOST driver, I decided to follow the instructions to use the ‘old’ SD driver and now I could install the Jarvis testbuild Beta5 without any problems. So, for those who are getting EXT4-FS errors after upgrading to 2015.12-1, please read this thread: Not booting after December update - #54 by Theetjuh