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Xbox360 Forums => Xbox 360 Hacking Forums => General Technical Hacking Discussion => Topic started by: jameswalter on December 14, 2005, 12:51:00 PM

Title: Media Flag
Post by: jameswalter on December 14, 2005, 12:51:00 PM
If the media flag is the only thing that seems to be stopping us...is is possible that something could be developed to go inline with the DVD-Drive SATA connector and intercept the signal that gives the media code and modify it to look like a pressed disc?  This may not help with homebrew but it may help run backups.
Title: Media Flag
Post by: TracerX on December 14, 2005, 12:55:00 PM
Don't think so. Removal of the media flag should throw off the checksum. Good thought though.
EDIT: Just realized you were talking about the media code of the disc. Definitely an interesting idea but how and when is the media code called up would be the question.
Title: Media Flag
Post by: lordvader129 on December 14, 2005, 01:39:00 PM
QUOTE(jameswalter @ Dec 14 2005, 01:58 PM) View Post

If the media flag is the only thing that seems to be stopping us...is is possible that something could be developed to go inline with the DVD-Drive SATA connector and intercept the signal that gives the media code and modify it to look like a pressed disc?  This may not help with homebrew but it may help run backups.

yes, this could theoretically work (in fact i believe this is how modchips for the sega saturn work)

the trouble is, as tracer said, knowing how and when the media code is read, and also being able to insert this data into any encryptions or checksums that are running as well

i do however feel this is a potential avenue for modding if it turns out we cant load anything into system memory past the hypervisor
Title: Media Flag
Post by: Arakon on December 19, 2005, 04:51:00 PM
opposite spin? uh?
Title: Media Flag
Post by: lordvader129 on December 19, 2005, 05:19:00 PM
QUOTE(globe_guyx @ Dec 19 2005, 03:50 PM) View Post

As for xbox1, its disc type was read as "***XBOX**DVDROM***"only at game launch..  Nowhere else was it referenced in the kernel source..  I tried to get Alcohol to burn this as booktype and failed..  Perhaps the fact that xbox drives had opposite spin was an issue..  If thats the case, perhaps transposing the image byte by byte?

thats because xbox dvdrom isnt a bitsetting, its the media code, it cant be changed on recordable media (its set on the disc at the factory)
Title: Media Flag
Post by: jameswalter on December 19, 2005, 05:38:00 PM
Right.  Its just not something that can be changed with how the media is burnt.  The change would need to be with the DVD-ROM firmware (always sends 360 disc media code no matter what) or with something inline with the SATA cable (intercepts the media code and changes it to the 360 disc one).
Title: Media Flag
Post by: jameswalter on December 20, 2005, 03:04:00 PM
Upon further thinking about PS1/PS2 modchips and how they operate, it seems that they do something similar to what I first mentioned.  I believe they simply give the OS false data indicating that the security features on the disc are present and the OS then initiates the startup of the disc.  It is interesting to note how many wires are required and the complexity behind these modchips (PS2 at least).
Title: Media Flag
Post by: Tobb555 on December 20, 2005, 03:27:00 PM
with the ps1/2 you can just get those hot swap disk that allow you to play backups and other regin dvds. why sony allows the company to make them is beyond me but no modchip is needed unless you want to run unsigned code. But for backups all you need is a hot swap disk. Forget the offical name of them.
Title: Media Flag
Post by: crosseye on December 20, 2005, 04:00:00 PM
semi true Tobb555. You can use a swapdisk, but you have to do some case modding so you don't have to eject to swap discs. You could also use the PS2 form of a softmod on a mem card. However, not all the games will load from the HDD.
Title: Media Flag
Post by: jameswalter on December 20, 2005, 04:11:00 PM
Right...but I'm mostly referring to the physical modchip that has 20-30 wires.  At least it did when I modded mine, I know they have gotten more advanced.  The protection behind the PS2 discs is bad sectors that can't be reproduced with a burner (if memory serves me correctly).  The newer modchips also detect the type of disc (PS1, PS2, DVD) and auto boot with the correct sequence sent to the OS (or whatever is controlling it).  I'm thinking something like that would need to be done to play backups....unsigned code however is a completely different issue.
Title: Media Flag
Post by: evilkleen on December 24, 2005, 09:28:00 AM
hmmmm.... highly interesting...  pop.gif
Title: Media Flag
Post by: Lysip on December 24, 2005, 01:12:00 PM
QUOTE

As for xbox1, its disc type was read as "***XBOX**DVDROM***"only at game launch.. Nowhere else was it referenced in the kernel source.. I tried to get Alcohol to burn this as booktype and failed.. Perhaps the fact that xbox drives had opposite spin was an issue.. If thats the case, perhaps transposing the image byte by byte?


Are you speaking of the media flag checks? i must assaume you have never see the kernel source ortherwise you might know what you are talking about.
Title: Media Flag
Post by: stevewal on December 28, 2005, 07:35:00 AM
Yea I think you've got a good point there james.
There's so much emphisis put on running unsigned codes, that MS has consertrated a huge amount of effort to prevent this. I'm sure the way you have described is what we'll see the first mod chips do. Oh and by the way, I fited a ps2 mod chip a few months ago, and I think it only had about 7 wires.
Title: Media Flag
Post by: tiggersbowl1 on December 28, 2005, 09:17:00 AM
I am pretty sure that the least number of wires on  a ps2 chip is with the duo and ice code, that has 17, unless of course you are referring to one of the chips that will fit only on a version 4 or something.
Title: Media Flag
Post by: lordvader129 on December 28, 2005, 10:42:00 AM
QUOTE(stevewal @ Dec 28 2005, 08:42 AM) View Post

Yea I think you've got a good point there james.
There's so much emphisis put on running unsigned codes, that MS has consertrated a huge amount of effort to prevent this. I'm sure the way you have described is what we'll see the first mod chips do. Oh and by the way, I fited a ps2 mod chip a few months ago, and I think it only had about 7 wires.

was it a no-swap chip? AFAIK there are 2 kinds of ps2 chips, one that prevents a reset when you eject the tray (you still have to use swap magic discs) and one that bypasses the media checks entirely (no-swap)