PS2 Swap Trick Question

Dariusc123456 · Post by **Dariusc123456** » Sun Jun 21, 2009 8:54 am

I have a question about the ps2 swap. I heard numerous times that you dont need a modchip, or a swap disc to play psx backups. Since the ps2 could do that, is it possible that it could run psx homebrew on the ps2?

cosmito · Post by **cosmito** » Sun Jun 21, 2009 11:23 pm

As you know this is a development forum. If you have development questions to post, then you're welcome to post them. For any other type of posts you have plenty of other forums.

Dariusc123456 · Post by **Dariusc123456** » Mon Jun 22, 2009 1:00 am

This is a ps2 Development question. It may not be a direct question, but its a related one.

Dariusc123456 · Post by **Dariusc123456** » Tue Jun 23, 2009 10:35 am

Let me just explain why I ask if psx homebrew can run on the ps2.

I was bored one day so I started to transfer my MC files to one another. When I place a ps1 mc into my ps2, I copied one of the files onto the ps2 mc. I thought that the ps2 can only have ps2 data on the mc. So my plan was to make a small installer using the PSX SDK to install the FMCB to the ps2 memory stick. I dont know how I am going to do it, but it should be possible if the ps2 runs psx homebrew.

J.F. · Post by **J.F.** » Tue Jun 23, 2009 1:02 pm

You need to boot a PSX disc to run in PSX mode on the PS2. There might be a way to trigger it in another fashion, but I've never seen or heard of any other method. To boot PSX discs on the PS2, you need a modchip or swap discs.

So you can make your own PSX homebrew discs, and you can run those on the PS2, but you will need a modchip or swap discs to do so. If you could make plain PSX homebrew that would install FMCB without a modchip or swap discs, it would already be all over the internet.

dlanor · Post by **dlanor** » Tue Jun 23, 2009 11:21 pm

Dariusc123456 wrote:Let me just explain why I ask if psx homebrew can run on the ps2.

I was bored one day so I started to transfer my MC files to one another. When I place a ps1 mc into my ps2, I copied one of the files onto the ps2 mc. I thought that the ps2 can only have ps2 data on the mc.

The PSX files are just raw data files, limited to be precise multiples of 8192 bytes. Such files can be stored on any generic file storage devices, including PS2 memory cards, and the Sony browser of the PS2 supports this for backup purposes (though it adds a containing folder for each PSX gamesave on the PS2 MC).

However, this does NOT mean that such PS1 gamesave backups on a PS2 MC can be accessed from any PS1 game (or homebrew). That is strictly impossible, since only PS1 devices are accessible when the console is running in PS1 mode. Such backups must be restored to a PS1 MC before they can be accessed from the PS1 games (or homebrews).

So my plan was to make a small installer using the PSX SDK to install the FMCB to the ps2 memory stick. I dont know how I am going to do it, but it should be possible if the ps2 runs psx homebrew.

No, that is impossible, because in PS1 mode there is no way to access the PS2 memory cards.

The PS2 can run some PS1 homebrews, but only in PS1 mode, meaning that such homebrews don't have access to all the stuff used by PS2 homebrews. I'm not sure of all the details in the remapping, but basically it boils down to the fact that convenient (driver-supported) access is possible only for those devices which a real PSX/PSOne had.

Best regards: dlanor

Dariusc123456 · Post by **Dariusc123456** » Wed Jun 24, 2009 12:05 am

J.F. wrote:You need to boot a PSX disc to run in PSX mode on the PS2. There might be a way to trigger it in another fashion, but I've never seen or heard of any other method. To boot PSX discs on the PS2, you need a modchip or swap discs.

So you can make your own PSX homebrew discs, and you can run those on the PS2, but you will need a modchip or swap discs to do so. If you could make plain PSX homebrew that would install FMCB without a modchip or swap discs, it would already be all over the internet.

Check something like this http://www.youtube.com/watch?v=kDpIHcRiraQ

My question is related this this method. Running a PSX game on the ps2 without a modchip, swap-disc, or MC exploit.

Dariusc123456 · Post by **Dariusc123456** » Wed Jun 24, 2009 12:08 am

dlanor wrote:
Dariusc123456 wrote:Let me just explain why I ask if psx homebrew can run on the ps2.

I was bored one day so I started to transfer my MC files to one another. When I place a ps1 mc into my ps2, I copied one of the files onto the ps2 mc. I thought that the ps2 can only have ps2 data on the mc.
The PSX files are just raw data files, limited to be precise multiples of 8192 bytes. Such files can be stored on any generic file storage devices, including PS2 memory cards, and the Sony browser of the PS2 supports this for backup purposes (though it adds a containing folder for each PSX gamesave on the PS2 MC).

However, this does NOT mean that such PS1 gamesave backups on a PS2 MC can be accessed from any PS1 game (or homebrew). That is strictly impossible, since only PS1 devices are accessible when the console is running in PS1 mode. Such backups must be restored to a PS1 MC before they can be accessed from the PS1 games (or homebrews).

So my plan was to make a small installer using the PSX SDK to install the FMCB to the ps2 memory stick. I dont know how I am going to do it, but it should be possible if the ps2 runs psx homebrew.
No, that is impossible, because in PS1 mode there is no way to access the PS2 memory cards.

The PS2 can run some PS1 homebrews, but only in PS1 mode, meaning that such homebrews don't have access to all the stuff used by PS2 homebrews. I'm not sure of all the details in the remapping, but basically it boils down to the fact that convenient (driver-supported) access is possible only for those devices which a real PSX/PSOne had.

Best regards: dlanor

I think I understand, but I am a testy person and will just try just to make sure.

J.F. · Post by **J.F.** » Wed Jun 24, 2009 7:37 am

Dariusc123456 wrote: Check something like this http://www.youtube.com/watch?v=kDpIHcRiraQ

He ran his backup by disabling the sensors related to the discs, putting in the ORIGINAL disc, allowing the PS2 to recognize it, then pulling it out (relying on the disabled sensors to not tell the PS2 the disc was changed), then putting in a copy OF THE SAME EXACT DISC and telling the PS2 to run it. Seriously, Dude, get a modchip or Swap Discs.

Dariusc123456 · Post by **Dariusc123456** » Wed Jun 24, 2009 7:56 am

J.F. wrote:
Dariusc123456 wrote: Check something like this http://www.youtube.com/watch?v=kDpIHcRiraQ
He ran his backup by disabling the sensors related to the discs, putting in the ORIGINAL disc, allowing the PS2 to recognize it, then pulling it out (relying on the disabled sensors to not tell the PS2 the disc was changed), then putting in a copy OF THE SAME EXACT DISC and telling the PS2 to run it. Seriously, Dude, get a modchip or Swap Discs.

Lol, I meant this is what I was talking about. I has a swap disc, but it broke, and I am going to soon install FMCB through some type of way.

I am not really talking about what method that person did, but I am talking about the ps2 swapping. My main question was Can ps2 run PSX Homebrew. and since someone explain to me that its impossible to save things to the ps2 mc, then I am going to try something else in mind. My whole purpose of this thread is to get answers about my question, which is all I really need to know.

Dariusc123456 · Post by **Dariusc123456** » Thu Jun 25, 2009 10:20 am

Ok, I bought a Game Shark, and it wont run. It gives "Disc Cant be read" crap, and that annoying ps2 make a craping sound when its trying to load the disc. Whats the problem?

J.F. · Post by **J.F.** » Thu Jun 25, 2009 1:15 pm

Dariusc123456 wrote:Ok, I bought a Game Shark, and it wont run. It gives "Disc Cant be read" crap, and that annoying ps2 make a craping sound when its trying to load the disc. Whats the problem?

As far as I know, Game Shark doesn't boot backup discs. It's not a modchip, it's a cheat device.

zaphod · Post by **zaphod** » Thu Jun 25, 2009 5:58 pm

He's claiming the gameshark itself won't boot.

if it's a ps2 one, he is probably haveing the "ps2 cds slip" problem.

The ps2 spins ps2 cd media the fastest of all, and when the insides get dusty, the discs can slip, causing loud noises and read failures.

SOmetimes switching to vertical helps, but not always.

If it's a ps1 gameshark, then it's probably a defective disc.

Dariusc123456 · Post by **Dariusc123456** » Thu Jun 25, 2009 9:05 pm

I might clean out my ps2 today. I know there is some dust in it, so I will see what I can do for it.

SOmetimes switching to vertical helps, but not always.

I dont get what you mean. How can switching it to vertical helps? And where can the dust buildup at that cause the disc to slip?

J.F. - You know as well as I do that GS, AR, CB, can copy data from and to the MC. All I really am trying todo now is install the FMCB. So please J.F. drop that attitude of yours.

Post by **Herben** » Mon Aug 31, 2009 3:15 am

Ok, first I just want to confirm what dlanor has said about PS1/PS2 modes and cards. For all practical purposes, you cannot access PS2 cards in PS1 mode. I wouldn't waste any time on that.

But on to your other question, the swap trick should work for PS1 homebrew if it works for copies. I do know, however, that there are some licensing checks done in the PS1 portion of the BIOS that will stop the disc from booting(black screen) if the disc doesn't contain the correct license info for your console region. You can resolve that by using something like HitLice(http://hitmen.c02.at/html/psx_tools.html) to patch your disc ISO before burning.

I have a modchip in my PS2 so I don't have to dick around with swapping. I don't use my PS2 for PS1 dev though, I use an old grey PS1 for that. The PS1 mode on the PS2 is slightly different from a real PS1 in some respects. The GPU is emulated by the EE while the IOP pretends to be a regular PS1 CPU. The result is some timing quirks that make some games/homebrew not work right, if at all. With a bit of experimentation you can sort that out but that brings up your next problem: testing code.

Burning disc after disc is not only tedious but also environmentally unsound. Back in the day when the PS2 first came and I wanted to explore the PS1 mode of the PS2, I wrote a small PS1 EXE loader that I burned to disc which loaded a PS1 EXE from the PS1 memory card. That way I could test out my code by copying the new EXE to the card with my trusty PSX, put the card in the PS2 and boot my PS1 memcard loader app disc which then loaded the EXE from the card. Not the fastest process in the world but it worked and I was able to play around enough in the PS2's PS1 mode to satisfy my own curiosity.

My own suggestion to you would be to get an old PS1(the one with the Parallel I/O Port on the back) if you really want to hack around the PS1. I don't have any PCs set up that have ISA slots anymore so I can't use the good old ActionReplay + CommsLink combination these days. If you do, it's a very nice setup for dev/various hacking. I now use a "GameShark Pro"(aka "GS3", "ActionReplay Pro" or "AR3) which I've reflashed with two different loaders: one that communicates with PC via printer port and the other uses a serial cable. Transfer rates aren't super great but when you're only sending KBytes of code it doesn't really matter. :P

If you don't want to get a PS1 + AR, I'd suggest you at least get a modchip in your PS2. Not only will it make booting PS1 homebrew easier, it'll do the same for PS2 stuff. You can do a lot with FCMB but it's nice to be able to put any old ISO9660 disc in your drive and read it without having to do any crazy tricks.

Oh, and a final note: the first couple versions of the GameShark CD that came out for PS2 were very shitty. I think their method of making bootable PS2 discs needed a bit of revision and now they're decent. I imagine you either got one of the really old copies or your laser is going out.

Good luck. :)