solution to 3ds lack of slot 2 and harvest moon ds/megaman zx link features

[Piotyr]

Ok I have a 3ds, a r4i card and a rom of megaman zx (I own the real game but I like having all my games on one cart). There be an issue tho, I am missing out on boss fights! What I do to not do such?

[Garoth Moulinoski]

You're stuck. The only way around is to use a DS with slot-2 (DS/DS Lite).

[Piotyr]

No cheats or hacks that can unlock these features? For example is the data in the gba carts or does the data just unlock something?

[Garoth Moulinoski]

Oh. I wouldn't be surprised if there are cheats for those things. But I don't know any of them.

[FAST6191]

Many of the GBA slot bonuses were just checks for the headers but some did want/read the actual saves and megaman might have been one of them (granted you said ZX and I am probably thinking battle network) and unlike pokemon (see cory1492's pokepatch) I do not think it ever got a proper patch.

Desmume has the option to emulate/fake various types of GBA device being present so you could catapult your save across- many of these bonuses are one shot anyway (game is detected and extras unlocked for all time or the option to then unlock them is made). Click on emulation pulldown menu- GBA slot and the rest should be fairly obvious.

I know this is not in a hacking section but this is a hacking site and it might not be that hard to pull off- the GBA slot is mapped to 08000000 through 09FFFFFF in the DS memory (and only there) with it being used for nothing else other than the GBA slot so any reads to it will probably be the checks the game makes. To that end you might even find something in a text search of a plain text disassembly and from there it would be a trivial assembly hack (the process probably goes read memory- compare to this value, if equal jump to unlock bonuses function and if not then go back to game; you then get to change the initial read to the location of the jump or change the branch function that causes a jump). You might even be able to render this as a cheat though it could be in an overlay which are a pain to target with cheats (not that advanced but I prefer to edit a couple of bytes in the ROM rather than go through the motions there).

Edit- found a copy of ZX I was using for my docs. It seems the ARM9 and overlays are all compressed (easy enough to handle with current tools though) and it does a lot of operations with 8000000 which would frustrate my simple check method but still if you do see things poking around that memory location (especially 080000A0 and the next 16 bytes) you probably have your victim.

[Piotyr]

Well can we move this to romhacking and maybe get some help on this? I know it may seem kinda like piracy talk but there is a legit use for it now that nintendo removed slot 2.

[Jorpho]

If you insert either a copy of the GBA Megaman Zero 3 or Megaman Zero 4 in the GBA slot of the DS when starting a game. The bosses that were found in the GBA versions will be found throughout Megaman ZX. Do you have what it takes to defeat them?

I see.

The real question is, does the game do a one-time check and set a flag in the save file, or does it check whenever the game is started?

[Piotyr]

I am guessing its an each time boot so you can fight both boss sets. Both x3 and 4

[Jorpho]

Okay, so, if Desmume can do this thing, what if you create two savestates (it can do that, right?) at the title screen or whatever, with and without the GBA slot active, and compare them?