Should games that work with m3 work with r4?

So my friend made a homebrew DS game (not online yet). He tried it on his M3 and said it worked perfectly. He gave me the ROM and i try to use it on my r4 original and it won't work. I thought M3 and R4's were somewhat similare and they could play the same games. Any help would be greatly appreciated. THanks.

Yes they are nearly complete similar, only difference is a solder in the hardware. Could I test the ROM on my R4?

My friend doesn't want to share it (i don't know why, so dont ask -.-), but should I try patching it?

Depends. What library did he use to develop it? Newer builded ROMs with newer libraries won't rarely ever need DLDI patching.

I know he uses Virtual Game Maker if thats what your asking.

Yes. Then you'll need to DLDI patch it.