Guys, watch my original videos on the subject, they're in the spoiler at the bottom of the first post.
This bricker bricks DS AND DSi functionality on the 3DS system. If someone really, REALLY wants me to, I'll download another DSiware game off of the eShop (I have a bunch) and make a quick video showing it also bricks that functionality. I don't have any retail DSi exclusive cartridges, so I can't test that, but logic denotes that DSi mode is DSi mode, whether it's loading DSiware or a cart.
Old flashcarts won't launch from this because the carts need to pass the 3DS's header checks. After that, everything seems like it should be fair game just like the old systems, but you can't hot swap anything in either because of how the 3DS works, so that's still out of the question.
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I see three interesting points out of my testing:
1) that BOTH DS and DSi mode brick.
2) DS settings are likely corrupted, and as you see, corrupted to the extent that it makes the SM hang in 3DS mode when you try to access them.
3) Settings (some) can be uncorrupted/reset by changing your 3DS name/birthday, which then allows you access to your DS Message and Color. Upon attempting to launch anything that runs on DS or DSi mode, the settings recorrupt, and we're back at point 2, above.
--Changing settings doesn't unbrick
--Updating the firmware doesn't unbrick