As in, so finicky that half the time, the save won't write back to the internal ROM. I would have bought an EZ-Flash IV except that I wanted an RTC and this claimed to have one... but it didn't. And worst of all, nobody has any clue about this little-known cart or how to use it properly. I'd really love some clarification about the proper way to save on the thing. I hear it works really well with their other products like the N64 adapter though, just not for its native GBA - and so I'm selling it too if anyone's interested.