ROM Hack "Download play" mode documentation?

[cal64]

Hello!
I've been looking for documentation on the GBA's download play-like mode. I'd like to implement compatibility in a project.

Has it ever been documented?
If so, does anyone know where I could find said documentation?

Thanks for reading, any help is appreciated!

 

[zfreeman]

No idea. I'm a layman, but this might help.

http://problemkaputt.de/gbatek.htm

 

[Localhorst86]

While I wasn't able to quickly find any usefull documentation, this might help:

The term for this mode is called "multiboot".
I know that PocketNES for the GBA does have this feature implemented, maybe looking at that source will help: http://www.dwedit.org/gba/pocketnes.php

 

[FAST6191]

Multiboot is indeed the term you want
http://reinerziegler.de/GBA/gba.htm#Multiboot
http://www.devrs.com/gba/files/mbv2faqs.php
https://www.darkfader.net/gba/ has a bit under uart (higher up on the list) and multiboot (way down the bottom on the list on the side).
http://problemkaputt.de/gbatek.htm#gbacommunicationports

Flash carts ended up quite cheap and easy so most go for that but you should be able to get something done, it was nice for hardware for the time as well (Reiner Ziegler's site having some of the things done with it) but today we have a billion off the shelf programmable chips with more power that speak USB, bluetooth and any other number of comms protocols. Play with what you want to play with though and feel free to come back and share it if you want.