Check out this excellent report by Dutch journalist Max Vanderwerff who debunks the reports allegedly showing a video of a Buk-M1 launch:
http://7mei.nl/not-buk-m1-new-video-proof/
There is no doubt my mind that MH17 was shot down by a Ukrainian SU-25, possibly one of several Su-25s patrolling the skies that day to intercept a civilian airliner the downing of which was to become the "surprise" Poroshenko promised and which Kolomoiskii probably organized.