Part of it is about the battle between Sinclair and Acorn.

ARM only shows up on a white board on the background of a discussion towards the end. So it isn't 100% absent from this movie, but it is really about the conflict between Clive Sinclair and Chris Curry (just like "Pirates of Silicon Valley" is about the conflict between Steve Jobs and Bill Gates).

OK I watched the whole thing. Highly recommended! It is about the rivalry between Sinclair and acorn, where the head of acorn once worked for Clive sinclair. It is about the time before ARM.

Reminds me of the past, as my first computer was sinclair spectrum. Fun times!