A very helpful person at Arrow, a distributor of Winbond's chips spent the last few days trying to help me get this spec sheet. He was unable, due to Winbond ignoring all requests for detailed sheet, but still he did all he could. Thank you very much, Brandon.
Reverse engineering effort will continue.
KC So, Winbond's director of marketing, USA said their support resources are stretched too thin to allow them to email me a single 3MB PDF file with the specs, even if I agree to pay for it, sign an N.D.A., and agree to not contact them with any further questions.
EDIT: talked to them again, things are looking better. See post above this one...
Specifically I need them to give me the non-public specification sheet for W86L488Y. The public spec sheet lists device registers on pages 15-17, but does not list the bits in those registers and what they do - making it useless. The detailed sheet they refuse to help with lists those.