Generally the Kodi UI is always 1080p on android boxes, have you tried playing a 4k movie to see if it switches to 4k?Just bought a Minix X8-H Plus full refurbished etc. Easily installed Lollipop 5.5.1. Kodi installed and working perfectly, however, even tho the box details show 4K ability, the resolution on my TV or on Kodi only shows 1080p! Have I missed a step?
You should also make sure that the 4K file you are trying is compatible with the X8H-PlusOK, I think I've been sold a "Pup". Tried to play a 4K movie today (Jason Bourne) and the screen showed choppy large pixilation, stop start etc. So as I bought it on eBay, I've requested a return to seller and refund. How do I change the Lollipop Finless update back to the 4.2.2 Kitkat?