Some users of the 2DS have reported a problem in the touchscreen -- a "phantom stylus" depressing the upper left corner and cycling the screen endlessly. These units still are under warranty, but someone's figured out how to make the fix on your own.
Of course, that requires disassembling the entire unit and then filing down or covering some plastic "ribs" on components inside, which sounds like it falls under the "modified or tampered" provisions that nullify the 12-month warranty Nintendo devices carry.
But reader wardboi, who brought this to our attention, didn't want to lose his 2DS Friend Code, which he would if his defective 2DS was replaced with a new or refurbished unit. If you're facing the same dilemma, watch the video above.
Basically, there is a "problem zone" underneath the touchscreen assembly, where plastic parts of the 2DS' interior are prone to press up against the upper-left corner. This is solved by laying a small bit of electrical tape over one area, and then gently filing down a tab on the underside of the circle pad controller.
You'll need a needle file, a small-head screwdriver and some electrical tape, and nerve enough to disassemble and reassemble your 2DS. If you lack any of those components, just send the thing back to Nintendo. The handheld released October 12 so, of course, it should still be covered.
Nintendo 2DS Touchscreen Issue Glitch Problem Phantom Stylus FIX [YouTube via Reddit, h/t wardboi]