Cobra 2.1 IPL documentation?

ViperGC/Qoob/etc
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IxerxesI
Posts: 2
Joined: Wed May 24, 2017 12:34 am

Cobra 2.1 IPL documentation?

Post by IxerxesI » Wed May 24, 2017 12:46 am

Hi everyone,

I've been lurking this forum for years and have finally come to the point where I think I have a question worth asking.

I would like to run my gamecube that has a viper extreme with cobra 2.1 without a disc drive inserted, no this is not for a handheld, and yes I know that there are production drive emulators that exist. Now, I understand that there is some necessary communication between the disc drive controller and the Gamecube's processor that needs to take place in order for operation to continue smoothly, and I have thoroughly read YAGCD and threads on here about how that communication works with the original GC IPL. My question is, does anyone know the details of this communication as it occurs with cobra 2.1? I am inclined to believe that it would be very similar in terms of the drive commands that are issued but I can't find details anywhere. If necessary, I'm prepared to purchase a logic analyzer (or make one with an FPGA) and find out for myself, but I figured I would ask here first. I will be booting from external hardware using SWISS and would like to simply keep the system happy without the disc drive being present.


Thanks in advance!!
novenary
Posts: 1754
Joined: Mon Dec 30, 2013 7:50 am

Re: Cobra 2.1 IPL documentation?

Post by novenary » Wed May 24, 2017 8:30 am

I can add Viper support to iplboot, which should cover your needs.

Edit: I've added it, currently untested but feel free to try it out.
IxerxesI
Posts: 2
Joined: Wed May 24, 2017 12:34 am

Re: Cobra 2.1 IPL documentation?

Post by IxerxesI » Thu May 25, 2017 12:03 am

So you're implying that I should just put swiss on the SD card and iplboot will make my system boot straight to that?
novenary
Posts: 1754
Joined: Mon Dec 30, 2013 7:50 am

Re: Cobra 2.1 IPL documentation?

Post by novenary » Thu May 25, 2017 5:22 am

Yes, that's how it works.
Pezac
Posts: 2
Joined: Sat Jul 01, 2017 11:48 am

Re: Cobra 2.1 IPL documentation?

Post by Pezac » Sat Jul 01, 2017 12:03 pm

A BIOS to boot a SD file directly sounds great! Did you have a chance to try it on a Viper chip?

I have flashed the r2 BIOS file on my Viper but the result I'm getting is that the cube is always going to the regular boot with the walking cube. I have tried a SD card in both slots with a converter/card that works in regular SDLoad and Swiss. The BIOS flashed OK according to the flasher program.

I've looked into the code and from what I understand the BIOS "exits" to the regular boot if the file is not found - however it's hard to tell if that is the problem. I have double checked the dol file name on the SD card.
novenary
Posts: 1754
Joined: Mon Dec 30, 2013 7:50 am

Re: Cobra 2.1 IPL documentation?

Post by novenary » Sat Jul 01, 2017 4:38 pm

Oh, someone to actually test it, great! :D I have an idea what the problem may be, I'll update the repo tonight. It's most likely related to the viper header. I only have a Qoob pro myself, that's why I couldn't test it.

Edit: I've uploaded a new release, try it now.
Pezac
Posts: 2
Joined: Sat Jul 01, 2017 11:48 am

Re: Cobra 2.1 IPL documentation?

Post by Pezac » Sat Jul 01, 2017 6:48 pm

That was quick! I tested r3 and now it works fine from both slot A and B. I used Swiss as the autoload DOL and started another DOL from there. Thank you for the help! This is great because for me the internal flash storage transferring refuses to work plus the apparent bonus of skipping the BIOS UI.

One interesting thing about Swiss: it gave a message about initializing the DVD drive at start, I guess this is expected with a BIOS without drive initialization :)
novenary
Posts: 1754
Joined: Mon Dec 30, 2013 7:50 am

Re: Cobra 2.1 IPL documentation?

Post by novenary » Sat Jul 01, 2017 6:56 pm

Yep, indeed. The point of iplboot is to load and boot a dol as fast as possible, since I wrote it mainly for development purposes. This includes not initializing the DVD drive (which Swiss does anyway) and not playing the GC intro (though it could be done with hacks that I don't really want to get into).
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