Homebrew Are ROM Hacks Signed?

[Parax342]

So I want to get Newer Super Mario Bros. DS and Another Super Mario 3D onto a cartridge and i'm wondering if they would be signed as they are a patch of signed ROMs.

 

[KleinesSinchen]

Neither “New Super Mario Bros. (1)” nor “Super Mario 64 DS” are digitally signed. Signatures were introduced with the DSi. All DS games released before the DSi were put on a whitelist.

The DSi and the 2|3DS (without CFW) check DS software before starting:

* Does the game have a valid signature?
* If not: Is it on the whitelist?

If none is the case: “An error has occurred.”

Changing anything on a digitally signed file makes the signature invalid. That is the purpose of a signature. Creating valid signatures for the DSi or 3DS requires a private key only Nintendo has.

Flashcarts bypass this by embedding at least parts of ROMs on the whitelist.
Better/longer explanation:
https://hackmii.com/2010/02/lawsuit-coming-in-3-2-1/

“DS-repros” are usually very cheap flashcarts with their micro-SD slot hidden/closed autobooting a single ROM.