Flash maps look tidy in a spreadsheet and messy on the line. When Desktop Leafpoint joins a Firmware Delivery Partnership, one early artifact is a flash budget that manufacturing and field support can both read.
Leave margin you can explain
Reserve space for logs, future certificates, and the recovery image you hope never to use. If margin is zero on day one, say so — and accept that a feature request later may force a hardware change.
Name the writers
Which process is allowed to write which region? Application firmware that casually rewrites calibration data will haunt you. Make the forbidden writes loud in code review.
Align with the programmer script
Contract manufacturers follow scripts, not wiki poetry. Give them a versioned map and a verification step that fails closed. If your programming fixture needs a different layout than development boards, document both.
Revisit after every spin
A respin that “only” changes a peripheral can still shift how much you need for drivers and buffers. Treat the flash budget as a living document in the engagement notes, not a one-time slide.