N64 Gameshark

[LeatherRebel5150 | 1,056]

I came across my gameshark while cleaning yesterday. When I was a kid we used this thing all the time for multiplayer Goldeneye, such good times. Anyway I went to boot it up and it seems to half work. It's a v3.1, parallel port, sparkly plastic, LED counter. It counts down and shows the gameshark logo screen but then goes directly to the game. It's not allowing me to choose any codes. I know these things have a reputation for needing reflashed. But that usually has the symptoms of not booting at all, while this one does but just skips the menu part. 

Anyone have any experience with this scenario and how to get it back to letting me choose the codes?