White gets it.
The partial block is completely ignored for purposes of determining possession, since it occurred either in or behind the expanded neutral zone (2 yards downfield).
Once R (the receiving team) is first to touch (or be touched by) a scrimmage kick beyond the ENZ, it will be first down for whichever team is in possession at the end of the down. Rule 5-1-3(f).
Please note that R's touching is ignored if he is pushed or blocked into the ball by K.