Execrom not detecting SCC

By CapnCrunch53

Supporter (2)

CapnCrunch53's picture

01-12-2022, 13:24

Heya, new member here looking for some guidance. I'll try to give as much info as I can without making wall of text.

My setup: I have a 64KB FS-A1, and a SD Mapper & Megaram 512KB. Not the most ideal setup, I know. I'm also using a Salamander cart with a taped pin in the second cartridge slot for SCC.

Background: I'm on a mission to get Metal Gear 2: Solid Snake working on it. Most everything else I want to play works fine with SofaRun. I'll spare the details, but first I tried loading disk versions of the game, but they would never finish loading - I eventually realized the system was running out of RAM since MSX-DOS2 takes over 64KB. I then tried running the ROM with Sofarun - which works! - but is extremely slow, we're talking 20s wait times between screens.

Here's where I'm at now: I've got MSX-DOS 1 set up on an SD card, and I'm booting into that in Megaram mode, and using ExecROM to launch the game. And it works! It actually runs at a proper speed, and is totally playable.

Here's the catch: ExecROM can't find the SCC. Specific error message is: "SCC/SCC+ not found or piggybacked with MegaRAM".

Some additional info:

  • Using this Salamander cart for SCC works just fine when using SofaRun to load games (but SofaRun's not an option for MG2 because it's too slow).
  • ExecROM does NOT detect SCC whether I'm in MSX-DOS1/Megaram mode or MSX-DOS2/Mapper mode.
  • I've tried every version of ExecROM I could find: 1.0, 1.1, 1.2b, 1.2c, and 1.2f.
  • I've tried some other ROM loaders in MSX-DOS1 but none were able to successfully load a rom.
  • I've also been using Contra as a control test, since that works fine in SofaRun. ExecROM has the same problem with it; that is, this isn't specific to MG2.
  • I did notice in the source notes for ExecROM 1.1a that SCC detection was disabled a few times throughout its development. Unfortunately, I can't find any source code newer than that, but it makes me wonder if it's still disabled, or if it's something with my setup?

So I don't really know where to go from here and was hoping somebody has advice for getting this working on my setup. I know the standard advice is get a Carnivore2 or a MegaFlashRom SCC+ SD, but I simply cannot afford them right now, and I feel like I'm so close to having this working with the cart I've got. The fact that ExecROM doesn't detect SCC in MSX-DOS2 either gives me hope.

Let me know what you think, I'll be so happy if I can get this working!

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By OeiOeiVogeltje

Paragon (1426)

OeiOeiVogeltje's picture

01-12-2022, 17:31

maybe try loadrom.com?

By djh1697

Paragon (1694)

djh1697's picture

01-12-2022, 22:12

SCC and MegaRAM will not work in the same slot, from what you have said you don't seem to be doing that.

There is a list of patches that you could try.

https://old.msxbasic.com/sites/cybernostra/index.php/component/content/article/180-execrom?catid=82:msx-software&Itemid=225

Hopefully, this will resolve your issue! If it doesn't work try swapping the ports rounds.

Update - the link appears not to work, but there is a patch somewhere, I just seem unable to find it, it will be a .XPC file.

By CapnCrunch53

Supporter (2)

CapnCrunch53's picture

02-12-2022, 00:52

OeiOeiVogeltje wrote:

maybe try loadrom.com?

I have actually tried with Loadrom v1.97. This is the output it gives, and it never progresses past this point. I get a similar result with Contra. I'd like to try an older version but I haven't found one yet.

djh1697 wrote:

SCC and MegaRAM will not work in the same slot, from what you have said you don't seem to be doing that.

There is a list of patches that you could try.

https://old.msxbasic.com/sites/cybernostra/index.php/component/content/article/180-execrom?catid=82:msx-software&Itemid=225

Hopefully, this will resolve your issue! If it doesn't work try swapping the ports rounds.

Update - the link appears not to work, but there is a patch somewhere, I just seem unable to find it, it will be a .XPC file.

Ok, I tried this (mgear2.xpc was actually in the extras folder that came with ExecROM v1.2f, so I added it to the SD card), and now we're making progress:

With the patch file present, if I type execrom /M mgear2, it does not detect the SCC, and it loads the ROM, patches it, and reboots the MSX. But then, after that reboot and continuing past DeskPac, if I type execrom mgear2, it detects the SCC!

And it does indeed try to use the SCC ingame - except that it sounds horribly out of tune. Here is a recording I made of the entire booting and loading process - if you skip to 1:50, you can hear what I mean about the music being out of tune:
https://www.youtube.com/watch?v=YzTUelArVHc

It's so close to working!

By Manuel

Ascended (19227)

Manuel's picture

02-12-2022, 07:54

Did you try the disk crack from 1997 with the English translation using the SD mappper in memory mapper mode? That always worked fine on my MSX2 with 512kB RAM.

By djh1697

Paragon (1694)

djh1697's picture

03-12-2022, 00:48

Do other SCC games loaded using execrom give similar results? I had a brazilian MegaRAM that had being upgraded to 1Mb and that worked fine with MG2, I sold the device soon after I got a MFRSCC+.

LoadROM does not work with a MegaRAM but uses paged RAM in your MSX. The issue is that MSX RAM is banked in 16k blocks, whereas the Konami devices are paged in 8k blocks, so I believe you would need an MSX with a 1Mb mapper to run MG2.

I think I have located the XPC file you need,

https://frs.badcoffee.info/patches.html

After viewing your video again, I do not think the SCC sound is getting implemented. It sounds like it might just be the PSG?

The way you are patching the file is incorrect, I cannot find the correct instruction to do it, the command line would be something like execrom mg2.rom /(unknown):mg2.xpc