SNES Neo Myth FLash Cart

MottZilla · Post by **MottZilla** » Wed Mar 31, 2010 11:23 am

You'd have to ask bunnyboy. But it seems that updating the Boot ROM isn't needed to do such an update.

mic_ · Post by **mic_** » Sun May 02, 2010 12:47 pm

I've added support for game genie codes to the Myth menu: http://www.youtube.com/watch?v=c8ZfmludfKA

And here's the menu binary for those of you who own a Myth: http://jiggawatt.org/badc0de/myth_menu-0.22.zip

mic_ · Post by **mic_** » Tue May 04, 2010 1:23 pm

I've now added support for Action Replay codes as well (including those that affect RAM): http://jiggawatt.org/badc0de/myth_menu-0.23.zip

Eyedunno · Post by **Eyedunno** » Tue May 04, 2010 4:21 pm

mic_ wrote:I've now added support for Action Replay codes as well (including those that affect RAM): http://jiggawatt.org/badc0de/myth_menu-0.23.zip

Holy crap, that's amazing, considering even Game Genie codes on the PowerPak are presently broken, or so it seems. I still feel like the PowerPak is the better piece of hardware, but thanks to you, the Myth clearly has the better menu.

MottZilla · Post by **MottZilla** » Tue May 04, 2010 7:50 pm

What do you mean broken? Are you sure the Game Genie codes are even valid Game Genie codes? As I recall you can make a code that looks valid but actually is not.

mic_ · Post by **mic_** » Wed May 05, 2010 2:20 am

That should be easy to find out. Just try the same code in BSNES and see if it has the intended effect.

Eyedunno · Post by **Eyedunno** » Wed May 05, 2010 4:45 am

MottZilla wrote:What do you mean broken? Are you sure the Game Genie codes are even valid Game Genie codes? As I recall you can make a code that looks valid but actually is not.

They're not codes I made myself; they're codes from code books. For example, in Street Fighter II (the original):

Code: Select all

DAB8-A761 Do special moves by just pressing buttons (may make Fireballs lower)

This works on an original Game Genie and in emulators, but not on the PowerPak.

Heinz2001 · Post by **Heinz2001** » Wed May 05, 2010 8:03 am

I also have problems using GG code for snes powerpak.

read here:
http://nesdev.com/bbs/viewtopic.php?t=5708&start=300

This codes (CB83-8F9A and 6D83-849A) work on bsnes but not on powerpak.

MottZilla · Post by **MottZilla** » Wed May 05, 2010 12:21 pm

For those with problems, it's not some codes don't work for you, but no codes at all work for you?

mic_ · Post by **mic_** » Wed May 05, 2010 12:52 pm

Looks like those codes Heinz mentioned reference bank C7, which would have to be a mirror of some lower bank because the game in question is only 2 MByte. I bet that's why the PP fails with those codes. I know my patcher in the Myth menu would fail with those codes, because I don't take mirroring into account.

Eyedunno · Post by **Eyedunno** » Wed May 05, 2010 3:32 pm

MottZilla wrote:For those with problems, it's not some codes don't work for you, but no codes at all work for you?

I honestly hadn't tried too many. Just now, some codes I tried DID work. They were:
(in Lemmings)

Code: Select all

31B6-6FAF + 18B6-64DF   Each saved lemming counts as two

(and in Mortal Kombat)

Code: Select all

C9B2-17AF       Infinite time

However, the following codes did NOT work in Mortal Kombat II:

Code: Select all

C2B1-14F7       Player 1 is invincible
6DC7-1DAA       Infinite time

So, hrm, apparently Game Genie support is incomplete then. In any case, it would be sweet not only to see this fixed, but also to get RAM-affecting AR codes.

Marcel · Post by **Marcel** » Thu May 06, 2010 3:42 am

Hi,
I helped to find the codes Heinz gave.

mic_ wrote:Looks like those codes Heinz mentioned reference bank C7, which would have to be a mirror of some lower bank because the game in question is only 2 MByte.

Indeed the gg code targets the fastrom mirror. This is the true address requested by the CPU on runtime.

As I'm not really a hardware guy, I have no idea how gg codes are implemented in the powerpack or the myth card. I don't quite get the mechanism behind mirroring/shadowing actually.

@Heinz
Could you please try the codes below, one after another. This is the same patch but applied to different memory banks.
bank $00: 6D83-649A
bank $40: 6D83-B49A
bank $80: 6D83-C49A
bank $C0: 6D83-849A (original code)

Besides the original, the other codes won't work with bsnes as this emulator does not always enforce mirroring on gg codes.

mic_ · Post by **mic_** » Thu May 06, 2010 3:59 am

As I'm not really a hardware guy, I have no idea how gg codes are implemented in the powerpack or the myth card. I don't quite get the mechanism behind mirroring/shadowing actually.

I can tell you how it works on the Myth because I wrote the code for it.

Whenever you run a game, the game ROM gets copied from the storage media (flash) to a PSRAM in the cartridge. The loader routine checks for each 1Mbit chunk that has been copied if any of the cheats the user has entered are targeting that 1Mbit chunk. If that's the case it overwrites the relevant byte in PSRAM using the Value byte from the cheat.

The problem is that I'm not taking mirroring into account, so bank C7 will be way outside the memory range being copied, and the cheat won't be applied. That's something I need to fix.

Heinz2001 · Post by **Heinz2001** » Thu May 06, 2010 4:03 am

@Marcel: I try this later today and report here.

Heinz2001 · Post by **Heinz2001** » Thu May 06, 2010 1:14 pm

@Marcel: I tried all Codes. Non of them worked.

Then i tried this codes:
http://www.gamegenie.com/cheats/gamegen ... crest.html

http://www.gamegenie.com/cheats/gamegen ... r2000.html

Of couse with (U) roms.

And they worked. It seems that the position is not accessible or our calculation is wrong.