Who knows, this may or may not be possible, but eh, dreaming is free, right?I was ready to say no to this idea however after some Googleing my answer may be different.
I don't have a DSi and I couldn't find much info on the EULA screen for the DSi but from DSiBrew it seems Nintendo was still using Opera for the browser on the DSi at that point and the last update for the internet channel in the DSi lists it as Opera 9.50 which should be vulnerable to this.
I have no idea how the EULA page on the DSi works. If the page is over https then this would fail, if it's not a web page but just plain text then this will fail, if it's actually WebKit and not Opera then this will probably fail. (This might affect WebKit too but I'm not sure.)
You can't just replace the EULA page for the DSi with this one and expect it to work. Someone will need to do the porting. Also does the DSi have ALSR/DEP? idk. This will be MUCH more difficult if it has ASLR. DEP is just an inconvenience, without ASLR it can be defeated pretty easily.
Someone familiar with the DSi scene might take a look at this as it might actually lead to something. Currently their only available exploit is FlipNote Lenny so if someone wants a SD-less + game-less DSi entry point then this has potential.
To add some information:Actually there is a chance that the DSi could be exploited with this. I asked the author of str2hax, and this is what he said:
Who knows, this may or may not be possible, but eh, dreaming is free, right?![]()
At any time (well, while not running another app), just go to settings > network > agreementThe EULA can only be read after formatting/setup, right?

Ohh, okay.At any time (well, while not running another app), just go to settings > network > agreement
that is correctThe only way to install unlaunch is hardmod if you dont have eny dsiware. right?
For now, "if you don't have any exploitable DSiware", yesThe only way to install unlaunch is hardmod if you dont have eny dsiware. right?