The .SRL is from Mario Kart DS (USA) (NDS) (Virtual Console), a Wii U software. Here is a patch to Mario Kart DS (USA), an NDS software.

I tried ndstool on the ROM, and one of the things it tells me is:

Code:

0x6C    Secure area CRC                 0x3B22 (OK, mask ROM)

does anybody now what a "mask" ROM is? and how to convert it into a decrypted ROM?

Retrogamefan has contributed some info:

Does anybody you know what the extra data is?

 

Have you tried dsi_srl_extract ?

 

That converts the bins from the SD card.

To convert it, then compare it with the USA cart version.

 

Lost my flashcard, so can't test it. If it is identical to the USA cart version, multiplayer would work.

 

No. This is not about modifying the Wii U VC to support multiplayer, this is about converting the DS ROM files that are used in Wii U VCs, and converting them into the common decrypted format of NDS ROM files. There is a thread about VC emulator modding in one of the Wii U forums.

 

Why do all my threads get hijacked?

 

IIRC you can use eNDryptS_Advanced_v1.2_NDS-iND to decrypt nds roms.

 

Yeah, last I checked NDS modcrypt is natively supported by the DS/DSi/3DS in DS mode. So you don't need to decrypt anything except whatever it is that contains the NDS rom.

 

I tried ndstool on the ROM, and one of the things it tells me is:

Code:

0x6C    Secure area CRC                 0x3B22 (OK, mask ROM)

does anybody now what a "mask" ROM is? and how to convert it into a decrypted ROM?

 

@Hiccup
The header is identical between the retail .nds and the WiiU .srl
There is extra data in the WiiU .srl from 0x1000-0x33FF, 0x3600-0x3FFF
If you encrypt the .nds, the data from 0x4000-0x1FFFFFF is identical