Ace Attorney Dual Destinies: doesn't boot due to unimplemented FindDLCContentInfos

[Miepee]

AM: Unknown am:app/am:sys command with header 0x10020104

https://docs.mikage.app/AMFindDLCContentInfos/

[neobrain]

There are already some stubs for related functions in platform/am.hpp and processes/am.cpp. Adding one more stub for this command should work to get the game running further.

Ideally we'd implement proper DLC support eventually. To implement these specific functions it'd be sufficient to reuse OnIPCGetProgramInfos. I'm not exactly sure how DLC is laid out on the 3DS filesystem though.