same problem here. (RP2, max2play 2.21, pre-installed kodi running –> 14.2)
black screen while fullHD videos or a rotating array of coloured squares appears.
Normal videos (SD) are working properly.
Video-Source (mkv, h264) cannot be the problem, cause same videos are working fine one separate raspberry pi 2 (without max2play) running openelec kodi 14.1 and without any special licences…
idea: in kodi 14.1 there is an option, which is missing in 14.2: in Settings -> Appearance -> File lists -> „Support browsing into archives“. maybe this causes the problem (afaik mkv is a container format)?