I just read in "Dealers of Lightning" [history of Xerox's PARC R&D lab] that an engineer optimized all the memory-handling bugs out of an early hardware prototy

I just read in "Dealers of Lightning" [history of Xerox's PARC R&D lab] that an engineer optimized all the memory-handling bugs out of an early hardware prototype/product, only to necessarily return them because a consumer software program wouldn't run without these known bugs present (this was in the days of hand-woven memory beads for bootROM). The fix was to re-implement the severe memory bugs in hardware, so the software would "work" correctly.