gbadev.org forum archive

This is a read-only mirror of the content originally found on forum.gbadev.org (now offline), salvaged from Wayback machine copies. A new forum can be found here.

Flash Equipment > r4i hack? (custom startup rom)

#173661 - Chris2027 - Wed Apr 21, 2010 9:26 pm

Hi to all,

I purchased a few "cheapest I could find" NDS carts with micro SD cards to install my own demo. This happened to be the r4i - which I believe its a clone from research.

My problem is that I am not interested in the menu system that the card firmware / software has, but I would like it to boot directly in to my own game.

Looking at the binary, called _DS_MENU.DAT, under a hex editor I believe this is just a NDS ROM (not encrypted). However renaming my own game to this file did not work. Infact it wouldnt boot any homebrew or alternative firmware / menu that I tried to replace it with.

So I guess my question is because I can not replace this ROM but how can I hack it? maybe I can have it launch my own ROM for me, or can I change an offset so it reads my ROM instead of itself?

If this is possible, how should I go about it? does anyone know how to find the ROM's main entry point? which disassembler should I use?

One of the options in the menu is to boot "media", this lauches the ROM called _DS_MSHL.NDS which CAN be replaced. I would rather skip this step though.

Many many thanks for tips, pointers or suggestions!

Chris.

#173662 - vuurrobin - Wed Apr 21, 2010 9:47 pm

see if this works:

http://fincs.drunkencoders.com/2010/04/13/r4i-christmas-hbmenu-bootstub/
_________________
my blog:
http://vuurrobin.100webcustomers.com/

#173706 - Chris2027 - Sun Apr 25, 2010 12:14 am

unfortunately that doesnt work with my version of the card. A bit of a shame because it looks exactly like what I need to do.. I'll see if I can find out how he did it to do something similar for my card.

Thanks very much for your response!

Chris