Ha! I have one of these that i built into a portable arcade machine. Some of the hardware has Xbox references on the pcbs, though i suspect the just didn't bother to remove from the source, though it could be surplus from earlier versions.

The games are hilarious and completely ripped off, some the Japanese only market versions, others weird mash-ups (like 8-bit Mario but with looney tunes characters).

Mine most certainly does not output 4k (what would a 4k gb-color emulator exactly look like? Gigantic, crisp pixels?)