First time trying out OSMC, used Kodi for the last few years. I have tried booting to OSMC with two different Model 2s, and two different SD cards. The only result I get is Rainbow Screen of Death, where all I see are colours, and all lights on the Pi go red.
I tried using the Windows installer, for the raspberry Pi 2, I even tried an older image, I redownloaded them both, all four times, it failed. I downloaded an image, unzipped it, and copied it to the SD card, and nothing happened.
Rainbow Screen very often indicates that the wrong image has been chosen.
Have you chosen the RPi2 image and are you 100% sure that you really have a RPi2? Especially as in the titel you wrote B+ which is a RPi1.
Maybe post a picture of the PCB so we can tell