If I recollect what I read, Siracusa and Gruber are saying Walter Issacson doesn't understand technology well enough to do justice to Jobs. They see possibilities missed in putting thoughtful questions about the technology side to Jobs and get answers from the man himself. Thrust of their criticism is not the characterisation of Jobs, but lack of knowledge of the technological canon that Jobs worked with. A better equipped author could have done more justice to Jobs life by avoiding those errors.

The discussion here was about the portrayal of Jobs himself in the book not the technical errors the biographer might have made, yeah, so I could have made that clearer.