This document is ready with a few minor clarifications.  It does not seem to require detailed Security Area review.

Section 2.1
"printable ASCII characters": Needs reference to what qualifies as "printable ASCII".

"color is a 32-bit numerical value": specify unsigned?

Section 2.4
"represented as a 4-byte number": In what byte order?

Section 9 "Protection": It's not clear who this is protecting from what.  Possible alternative title: "Recovering from segment failure".