In a post on the Romhacking.net message board, Farid (Kunio) raised the point about Nestopia mis-detecting a hacked Japanese ROM as US Region, so Nestopia selected to emulate a NES 4-player adapter instead of a Famicom 4-player adapter, so the game's 4-player mode stopped working.
Looking at the NES 2.0 specification, I see nowhere where it distinguishes games intended for the Famicom and games intended for the NES, or indicates what kind of peripheral is suggested for the game (ie, make Duck Hunt want a Zapper).
Obviously, this is an issue with Nestopia being too reliant on the ROM database, but wasn't NES 2.0 designed to answer the ambiguous questions that a ROM database would otherwise solve?
Looking at the NES 2.0 specification, I see nowhere where it distinguishes games intended for the Famicom and games intended for the NES, or indicates what kind of peripheral is suggested for the game (ie, make Duck Hunt want a Zapper).
Obviously, this is an issue with Nestopia being too reliant on the ROM database, but wasn't NES 2.0 designed to answer the ambiguous questions that a ROM database would otherwise solve?