I shouldn’t have tried to look at this and respond from my phone lol. Upon closer look, I don’t see the issue you’re pointing out. The logic seems clear, if second to last frame == 54 and last frame == 43 then… it does look like this is straight from your code here:
Which you provided as an example of how one might start going about getting the 60GHz radar frames.
However my observation still stands 
there isn’t a good reason, that I can think of, to interrogate these frames before processing. Especially given the processing does that anyway and discards any frame that doesn’t match.