Weird yellow colored Gameboy cartridge (4-in-1 Fun Pak)

[loopie | 51]

Hi all, I recently acquired from a friend a copy of 4-in-1 Fun Pak (DMG-F4-USA) that came with the manual, except the cartridge is completely yellow. I have never seen this before and can't find anything about it online. My friend told me that it was a rare variant, but doesn't have more info either. The cartridge itself looks pretty legit (it doesn't say 'GAME' like most bootlegs), the plastic feels exactly like a gray cart and there is the typical 'Made in Japan' and 'Pat. Pend' on its backside (hard to see on the pic). The only thing is that there is a sticker on the back that prevents one from opening it up without "voiding its warranty".

Does anybody have any clue about this? Any info appreciated!

[RH | 5,341]

It's an old school bootleg.  Crack it open and you should find an EPROM.  Does it feel like it bulges a bit?

[loopie | 51]

Thanks @RH. I cracked it open for science -- looks like you were right. Mystery solved! Thank you

[Tanooki | 5,189]

Wow that actually for whatever reason was really well done.  Unlike a lot of modern fakes who just put 'GAME' in the right font up there, that really tried to nail down the plastic entirely.  The amusing bit is, that game other than when it first came out and barely after has had so little value it makes you question, who, what, where, when and why on that even existing.