Oh you actually bought that one? Neat. Frankly my initial excitement of getting a Fire Bird has dwindled since we last talked about it but if I find an opportunity to get one then I certainly would consider it, lol.
If you've gotten the opportunity to dump the ROM from the working unit, can you confirm if it's identical to the common ROM? I'd also be interested in seeing what that weird link cable option at the bottom of the main menu does on real hardware, as going by emulation of the ROM, it still has the menu cursor for some reason and pressing the A button shows a loading dialog with changing hex values, which probably isn't how it's supposed to work? I'm willing to be proven wrong though. :p
The link cable thing didn't work when I tried it on cart. Probably doesn't activate unless you plug something into the link cable port. Maybe it's for copying codes between devices
Edit: Translation software says its for updating the device
Compared your ROM to the common ROM with WinMerge, and apparently there's a big number of differences in bytes between the two files. Notably, there's additions of large sections of "BANK XX" (X's being numbers) data in the common ROM that include the ROM header name and some other data in areas that aren't present in your dump, and vice versa. I'm not sure if it's the result of a custom mapper or what. If you got the same result for your dump during multiple attempts though then I guess it might be a different revision of the cheat card or something.
Also, interesting about the Fire Bird having the ability to update itself. Wonder how that was supposed to work. Did they provide a device to allow it to send updates downloaded from the internet from a serial port on a computer to the link port or did they have kiosks or something similar? Guess we'll never know until a boxed copy of this thing shows up that hopefully clears that up.