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Author Topic: Xbox/360 Demo  (Read 278 times)

lordvader129

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Xbox/360 Demo
« on: December 12, 2005, 09:06:00 PM »

not really, you can get game files from the ISOs and rawdumper that are floating around on the net, but its really no good until 360 is modded

it might be true that the demos dont have media checks (wouldnt be unprecendented) but they cant be used to load anything that does have a media check, nor can they be altered without invalidating the digital signature

demcompiling the binaries might help in understanding how stuff runs on a 360, but anyone doing that probably has access to a devkit anyway, and any dev documentation would be far more helpful
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running_wild

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« Reply #1 on: December 12, 2005, 09:06:00 PM »

To me, all this would mean is that we have another free xex.
(By free I mean we don't have to extract it using PI tools)

We can't modify the disk, all we can do is view it - as we could already do. Any modifications and the 360 (or even xbox for that matter) would chuck a stink about the invalid signatures.

I'm still learning, anyone feel free to correct me. (Be gentle   jester.gif )
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krayzie

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« Reply #2 on: December 12, 2005, 10:46:00 PM »

QUOTE(running_wild @ Dec 13 2005, 05:13 AM) View Post

To me, all this would mean is that we have another free xex.
(By free I mean we don't have to extract it using PI tools)

We can't modify the disk, all we can do is view it - as we could already do. Any modifications and the 360 (or even xbox for that matter) would chuck a stink about the invalid signatures.

I'm still learning, anyone feel free to correct me. (Be gentle   jester.gif )



well technically ...IF the demo disc doesn't have the proper media checks (which I doubt but you never know) you cannot alter the default.xbe/default.xex but you CAN burn the disc and run it. Therefore you have the possibility to edit anything besides the 2 executables (and perhaps anything else that is hash checked by the executables).
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lordvader129

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« Reply #3 on: December 13, 2005, 08:19:00 AM »

QUOTE(krayzie @ Dec 12 2005, 11:53 PM) View Post

well technically ...IF the demo disc doesn't have the proper media checks (which I doubt but you never know) you cannot alter the default.xbe/default.xex but you CAN burn the disc and run it. Therefore you have the possibility to edit anything besides the 2 executables (and perhaps anything else that is hash checked by the executables).

i think what the assumption was is that some dvd movies had playable xbox demos on them, and those didnt have proper media checks, so natually someone will assume (incorrectly) that nothing has proper media checks anymore
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krayzie

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« Reply #4 on: December 13, 2005, 08:56:00 AM »

Yeah I think MS would have to be very stupid to sign an xbe/xex and not add the xbox dvd media flag to it.
To my knowledge there are only a few discs with a cd-r and a dvd-rom flag in it.
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lordvader129

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« Reply #5 on: December 13, 2005, 09:50:00 AM »

QUOTE(krayzie @ Dec 13 2005, 10:03 AM) View Post

Yeah I think MS would have to be very stupid to sign an xbe/xex and not add the xbox dvd media flag to it.
To my knowledge there are only a few discs with a cd-r and a dvd-rom flag in it.

xbox Live arcade, and a few demos on movie cds are the only xbes i know of with no media check, both of which are freely distributed, and Live arcade requires a Live account and you have to pay for the minigames you download (its actually in MS best interest to not have checks in these, allows them to be distributed to greater numbers)

the emulator updte is the only xex i know of with no media check, same reasoning as above
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PS2MXBOX

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« Reply #6 on: December 13, 2005, 09:58:00 AM »

this may be stupid, but is the media flag by chance in a hex changable place? What I mean is, can we find the media checks by looking at the hex? (im a poet and i didnt even know it)
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krayzie

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« Reply #7 on: December 13, 2005, 10:16:00 AM »

there are programs that can dump the xbe/xex to find out what flags it got.
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PS2MXBOX

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« Reply #8 on: December 13, 2005, 10:18:00 AM »

well if we know the media flags, theoretically, can't we change the flag and shrink these raw dumps to fit on cdr (or even dvdr5 instead of 9) similarly to what happened with the original xbox rips?
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krayzie

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« Reply #9 on: December 13, 2005, 10:22:00 AM »

you can't change anything without invalidating the signature.
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lordvader129

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« Reply #10 on: December 13, 2005, 10:49:00 AM »

QUOTE(PS2MXBOX @ Dec 13 2005, 11:25 AM) View Post

well if we know the media flags, theoretically, can't we change the flag and shrink these raw dumps to fit on cdr (or even dvdr5 instead of 9) similarly to what happened with the original xbox rips?

if we could do that there would be no need to mod the xbox, as we could jusrt rip a backup, remove media check and run it, but as krayzie said this will invalidate the signature, its a nice little system of checks and balances
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PS2MXBOX

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« Reply #11 on: December 13, 2005, 10:56:00 AM »

not to jack this thread, but do dev kits have all the same encpytion and media checks and keys? can someone theoretically log what the dev processor is doing and make a chip that says any media with or without the signiture can run?
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krayzie

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« Reply #12 on: December 13, 2005, 11:05:00 AM »

I don't think dev kits have any protection as they are usually designed to run unsigned code.
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PS2MXBOX

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« Reply #13 on: December 13, 2005, 11:11:00 AM »

this will be my last post in this thread, but why cant we log the data off the dev kit processor and put that in a chip?
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lordvader129

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« Reply #14 on: December 13, 2005, 11:17:00 AM »

QUOTE(PS2MXBOX @ Dec 13 2005, 12:18 PM) View Post

this will be my last post in this thread, but why cant we log the data off the dev kit processor and put that in a chip?

the hard part of that is the chip part, how do you make the modchip? where do you install it? once its installed how do you get it load its code past the hypervisor? writing the code to ignore media checks and signatures is really the easy part when you look at the rest of it
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