Apple v. Franklin
The 1983 case that settled that object code and operating systems burned into ROM are protected by copyright.
Franklin Computer's Ace 100 was an Apple II clone that ran Apple software by shipping Apple's ROM code, copied wholesale. Franklin's defence went for first principles: machine code on a chip is part of the machine rather than a text, and an operating system is a process, not a work. Besides, Franklin argued, the only way to be compatible was to copy.
The trial court was partly persuaded; the Third Circuit was not. Programs are literary works whether in source or binary, in ROM or on floppy, and wanting to be compatible is a business goal, not a licence to copy. Franklin settled in 1984 and rewrote its firmware. From then on clone makers had to license or write their own — which is exactly what Compaq and Phoenix went on to do with the PC BIOS.