http://www.mediafire.com/?15tvlfababe716q A link to a number of awesome .mpk files In it is a 100% Blast Corps.mpk. The ED64 AND PJ64 Windows emulator are capable of saving Blast Corps to an eep4k file... Is it possible to get the .mpk file in the link above of Blast Corps into an eep4k that can be used with the ED64? With that the Rareware games 100% will be complete that I have! (Until they get Banjo Tooie working...;-))
You'll need to reverse engineer the format of both types of the saves; it appears simply cutting the save file out isn't enough to get it to work. You would have better luck with a tool to write the mpk save to a real memory pak and just going that route.
