yes, it is possible that homebrew can brick/damage a system. just read about the
ds bricker. although i do not believe it affects the dsi, and it only damaged early versions of the ds/ds lite. later versions only had their WIFI settings deleted. 99.99% of homebrew is competly legit and was never designed for malicious purposes.
download homebrew from filetrip:
http://filetrip.net/nds-downloads/games/
http://filetrip.net/nds-downloads/applications/
http://filetrip.net/nds-downloads/emulators/emulators-for-nds/
unless your friend is using the
diswarehax or a
cyclods ievo they will be running code in ds-mode. so question 2 may not have anything to do with their ability to run ds-mode homebrew on the dsi. there is no homebrew that "emulates" the ds on the dsi. the dsi can play files in ds-mode and dsi-mode. the dsiwarhax would allow them to run files off the dsi sd card, however, they would need to have purchased one of the exploited files before nintendo patched them/updated the dsi firmware. i'm assuming, if you are asking, that they don't have one of the exploited games.
your friend will need a
Flash Kit that can boot on the dsi in order to run homebrew. you don't need a tutorial. just drag/drop and enjoy. some software may require you to have files in the /data directory or ROMs in a specific folder. so read all of the included documentation.
-another world
