ROM Hack How do you convert Nintendo DS .SRL into decrypted .NDS?

[Hiccup]

I don't want a tool for decrypting DSiWare ROMs
I just want to know what a mask rom is and what this "extra data" in these particular (NDS) ROMs is!

 

[Hiccup]

Bump.

 

[Kajiarashi Suzaku]

I know these ROMs can be run in emulators
I just want to know what a mask rom is and what this "extra data" in these particular ROMs is!

I really don't know what is a Mask ROM and that extra data. But ROM usualy is a memory to store data inside. Looking in a article on Wikipedia:

The "Mask ROM (MROM) is a type of read-only memory (ROM) whose contents are programmed by the integrated circuit manufacturer (rather than by the user). The terminology "mask" comes from integrated circuit fabrication, where regions of the chip are masked off during the process of photolithography.

"In mask ROM, the data is physically encoded in the circuit, so it can only be programmed during fabrication."

Reading the Nintendo DS/DSi Enhanced/DSi Game Card Manual from official TwlSDK I found that info: Mask ROM are used on games with capacity between 64M and 512M. Rom with 1G capacity or larger was not planned to have support for mask ROM, only have support to a one-time PROM (programmable read-only memory). DSi-Enhanced, and DSi games only use the one-time PROM.

Probably its a specific type of data planned to be writed in the chip in the cart manufacture process.

 

[Hiccup]

Thank you for the info. But I still don't really understand the purpose of the differences between the normal USA ROM and the VC version (or if there really is any). But if you don't know, you don't have to answer.