Hmmmm, so my new rom didn't work quite perfectly, but the results are curious and nonintuitive, to say the least. Namely, the four codes all work brilliantly in the first area, but when you take any elevator down into another zone, two of them stop working (and it looks like if I use the fifth code, it does the same thing, such that only two of the five work all over the map). This is unexpected behavior to say the least since all that should be changing is the room data associated with the new map layer. I'm going to play around with the codes some more and see if there are alternate hex addresses that also work and are not affected by this, but welcome any advice how to work around this.
Oddly, all three of the obviated hex codes start with 45XX:XX, while the two that continue to work do not.
August 11, 2014, 11:25:24 pm - (Auto Merged - Double Posts are not allowed before 7 days.)
Hmmm, so I found a second set of addresses that each of those three codes also needs in order to function on the other side of an elevator. For SUPEAI, for example, you must enter not only 45A3:D5 but also 105A3:D5. The other two broken ones are similar. So now I'm wondering if there's a way to combine the two into a single GG code, or if it will just require two lines.
However, I also found that some complicated elevator trickery will eventually negate all three again, even with two codes entered for each function. I guess I'll have to see if the original 6 digit codes will even hold up to the same elevator madness, and if so, search for a third address for each one.
August 12, 2014, 11:56:54 pm - (Auto Merged - Double Posts are not allowed before 7 days.)
I figured it out--for the three codes in question, it turns out one code is required for each of the game's five areas. To use SUPEAI as an example again, all five of the following:
...must be used at once in order to enjoy the effect anywhere in the game. The other two (SSAEAI and SSPALI) follow exactly the same pattern. The ones that begin with 4 activate the codes in Brinstar (as you found originally), 8 in Norfair, C in Tourian, 10 in Kraid and 14 in Ridley. I still find this bizarre and difficult to explain, but at least my patched rom works like a charm everywhere now.
So I'm left with just a simple question: can five codes such as the list above be combined into a single Game Genie code that is any more specific than the original 6-digit code we started with?