Sorry about the title chaps, couldn't resist it!
The question is valid though, I have two IIe machines but only one of them will run ProDOS. The other states it will only run on an 'enhanced IIe'. I read that the 'e' referred to the enhanced model but ProDOS is looking for an enhanced enhanced computer!
What are the essential differences between these and is it possible to upgrade one to the other (by way of ROM replacement) or am I looking at a motherboard swap?