[Random Question] My hack size is 4mb...

Is it serious? It was 2MB an hour ago.
This is the first time it happens.

 

Could you have elaborated on that first?

 

You've obviously surpassed the 2MB mark and the disassembly automatically padded it to 4MB.

Also, this is not topic worthy. This could have, and should have, been asked in Basic Q&A

 

Um okay, i'm sorry, but I do not dare post in Basic Q&A, i don't know why
I read everywhere that a 4mb rom is dangerous for emulators, thats right?

 

Sonic 3D Blast is a 4MB ROM. Sonic 3 & Knuckles is a 4MB ROM. I'd hardly call either of them "dangerous". What does cause issues is when you surpass 4MB, then some emulators (and maybe hardware) won't load data from the end of the ROM properly, unless you use SSF2 bankswitching.

 

Oh my... ok, understood.
I will get some informations about SSF2

 

Where did you read this at?
You're saying you're reading it "everywhere", but it's a completely false statement.

 

Manner of speaking. '-'

On certain forums some months ago, when i have reached 2mb.
I have found a guide here to "use" the SSFII and i have apply it into my hack.

 

...

You don't need to.
All that's happened is that your hack has gone over 2MB, and the during the build process of the ROM, it gets padded to 4MB. That's it.
As long as you don't go over 4MB (you probably won't), there's no need at all to deal with SSFII's mapper stuff.

 

Ok, thank you!

 

...

Alright, I'm going to say this once, for everyone to hear. The generally accepted mapping maximum for Mega Drive/Genesis ROMs is 4MB, as the regions immediately following the end of the fourth MB have various designated uses already. You can, technically, flat map beyond that to about 10MB, but doing so breaks compatibility with a lot of things and is generally regarded as A Very Bad Thing™, and thus is definitely not recommended to ever do. Extending beyond 4MB without relying on flat mapping requires the use of a ROM mapper to swap blocks of ROM into the mapped area, allowing a ROM to look like a 4MB or less program without actually being such. You only need to use a mapper when going beyond 4MB. If your ROM is 4MB or smaller, then it is unnecessary. If someone insists you need a mapper at a ROM size less than 4MB, they're full of shit, and don't know what the hell they're talking about in general.

Got it?

 

You may have got the idea of 4MB being dangerous from SRAM. SRAM is commonly mapped to upper 2MB of a ROM (in case of Sonic 3, $200001 to $2003FF) which will break compatability with 4MB ROMs unless you properly switch between SRAM and ROM. However, unless you are dealing with SRAM, chances are 4MB ROMs will work the same as 2MB ROMs and require no extra changes.