ROM Hack How do I repack NDS ROMS using dslazy?

[MegaMario]

OK, I hacked my Mario Kart DS Rom to play beta tracks, but I don't know how to repack it. Can somebody help me? Here is where I got it:

http://wiki.pocketheaven.com/Dslazy

 

[FAST6191]

DSLazy is a frontend for NDSTool (amongst other things), my personal suggestion is to use NDSTool directly to reassemble the rom.
Use the following command with ndstool (either copy and paste or stick it in a batch file) in the same base directory as the extracted rom (the base directory is the one with the y7.bin , y9.bin, header.bin... and the directories overlay and data.

ndstool -c xmod.nds -9 arm9.bin -7 arm7.bin -y9 y9.bin -y7 y7.bin -d data -y overlay -t banner.bin -h header.bin

It might be worth using an earlier version of NDSTool as well as later versions can mess with some flashcarts patching mechanisms.
I have an earlier version on my site too if you want it (link in my signature).

 

[Foie]

Can I customize the track list for WiFi games this way?