compatible flash chips

[Nathanael Noblet]

Hello,
    I just received my EPIA 800 and am itching to get it up and running 
with freebios. I have flash parts for a board I was previously working 
on. I'd like to know if they are compatible, they are the same form 
factor (as in PLCC chips). The one in the board is a SST 39sf020a, and 
I have Winbond w29c020cp90b. How do I know if they are compatible? I'd 
rather not flash this and it not work, and then not be able to do 
anything with it...