CD32 Swap method - Page 2

Amiga1992 · 17 February 2016, 20:20

Quote:

Originally Posted by earok

Who actually owns the logo now, and would they be the only people able to contest a new commercial CD32 release?

There were some issues with this, I think there's a german company owning it, but their territory isn't world wide. It's very complicated.
There's also the people who made the C64 joystick computer thingy, the DTV. Those are American I think.

Retro1234 · 17 February 2016, 21:31

Quote:

Originally Posted by Amigajay

Well Piko Interactive are going to releasing 3 CD32 titles this year supposedly, maybe could ask them if they need a license and who from?

Not saying your wrong but I think someone has made a mistake this is like saying you cant make a floppy bootable - if there is any truth in it, you should be able to make as many bootable cds you like if you own the developers cd

What about something like the link below, could it work on CD32? FFS and RDB http://eab.abime.net/showthread.php?t=67898

Amiga1992 · 17 February 2016, 22:02

Quote:

Originally Posted by Boo Boo

I think someone has made a mistake this is like saying you cant make a floppy bootable

It's not the same issue, as discussed, the CD32 and CDTV need a certain file in there that only is injected by the official developers kit. It is not at all like a bootable floppy, which needs no such thing. Let's think of it as a licensed "bootblock" that can only be there if put by the official dev tools, otherwise it's "infringement".

Of course, no one can really get this because it hasn't been supported for decades (and buying a copy from someone or somewhere today doesn't amount to anything), so the point of who's enforcing the license is kinda moot, but that's how license/copyright vultures are like.

I am pretty sure that these morons would try to initiate action against anyone who bought an original copy of the developers' CD. Of course nobody has money to waste on taking it to court and proving them wrong, so they just go left and right scaring every fucking one.

Retro1234 · 17 February 2016, 22:08

Floppys and HD require a bootblock and CDs require the .tm you can add it without the developers kit. I dont know is it just a file that is checked or is it actually part of the boot process like RDB?

Commodore never licensed it - as far as I know it was free
or with the developers CD you can make as many bootable disks as you like.

the Floppy bootblock probably has copyright Commodore somewhere in it but it doesnt mean you neeeded a license.

Amiga1992 · 17 February 2016, 22:48

You're utterly confused about this, and comparing a boot block with these files seemes like it was a bad example given your response, so I'll let anybody else explain it to you in a better way because I failed.

To sum up, if the .TM files came with a developers license that you paid for, they are in NO WAY free. Acquiring a developers CD meant acquiring a developers license. And the stupidest part of this all is that today you can't go and acquire a dev license, so anyone making a fuss about it is just a tit.

Retro1234 · 17 February 2016, 22:59

Ok Akira

gulliver · 17 February 2016, 23:43

Just build a custom trademark file and make it public so that this issue never happens again with the CD32.

It is just a 2KB file for the CD32, I am sure we have plenty of coders that could help you on this.

Retro1234 · 18 February 2016, 00:06

Quote:

Originally Posted by gulliver

Just build a custom trademark file and make it public so that this issue never happens again with the CD32.

It is just a 2KB file for the CD32, I am sure we have plenty of coders that could help you on this.

Earok

earok · 18 February 2016, 06:25

Quote:

Originally Posted by Boo Boo

Earok

Haha, not me

I'd be willing to bet that the trademark file has to be exactly the same, or almost exactly the same, as the one that already exists.

Edit: But on the off chance it doesn't.. an "open source" Trademark file would be hugely appreciated.

Edit 2: Nope. I changed a single character in the trademark file (changing the C on Copyright to lower case) and it didn't work. I'm now very, very sure there's no way to make a CD32 bootable disc unless it contains an exact duplicate of either trademark file.

gulliver · 18 February 2016, 09:49

Maybe it is just some sort of CD32.tm checksum, so if that is the case, the contens could be altered as long as the result of the operation remains the same.

jbenam · 18 February 2016, 10:49

Quote:

Originally Posted by gulliver

Maybe it is just some sort of CD32.tm checksum, so if that is the case, the contens could be altered as long as the result of the operation remains the same.

IF it is a checksum, I can expect Commodore to have used some quite simple checksum back then as the CD32 wasn't a powerhouse and they needed to use some lightweight function to be quick enough to use during boot (CRC32?) and with the computing power we've got nowadays it should be pretty easy to generate a collision and create a valid file which has nothing to do with the original one while still having the correct checksum.

...I do believe we need Mr. Wilen's help here

earok · 18 February 2016, 11:35

I would have presumed that a copy of the entire trademark was in the rom (the tm is only 2k)

Having said that, I didn't spot a copy of it when I had a quick browse of it.

If it is a checksum - surely we could bruteforce a matching trademark.

Meshuggah · 18 February 2016, 12:30

The problem here is the content of the file I guess.
There's a possible solution to this: if someone would forge a file that would trigger a buffer overflow in the reading routine, a payload inside the file could then be ran to circumvent the check.
It's a long shot but maybe doable. That's only if a vulnerability exists in the reading routine tho

Retro1234 · 18 February 2016, 13:46

How can you create exactly the same checksum? and remeber it supports CDTV.TM - I just tried a empty file same size as CD32.TM but as earok had changed just one letter there was no chance.

Quote:

Originally Posted by jbenam

...I do believe we need Mr. Wilen's help here

Toni

would know can the CD32 handle a custom file system ie a bootblock

SkulleateR · 18 February 2016, 13:56

Btw. just had a look into cd32.tm and cdtv.tm .... cd32 file is exact 2KB and cdtv file is 22.152 Bytes ??? Are those the correct files (got it from developer kit) ???

Meshuggah · 18 February 2016, 14:00

If it's using crc16 or crc32, it's possible to generate a different file with the same size and hash and be done with it.

Retro1234 · 18 February 2016, 14:05

Yes thats correct CDTV.TM is bigger

Ok thanks Meshuggah

SkulleateR · 18 February 2016, 14:07

Oh if someone wants to try :

CD32.TM CRC32 -> E56C340F
CDTV.TM CRC32 -> 37C532D7

As I said, these are those files from Developer Kit 2.1

Didn´t check files from any CD32/CDTV Disk yet

Amiga1992 · 18 February 2016, 16:23

Great, I love where this conversation is going. I hope we can find an alternate and fuck the license vultures.

Meshuggah · 18 February 2016, 16:26

Idealy, someone should trace the CD32 bios to check how the file is verified.

17 February 2016, 22:08	#24
Retro1234 Phone Homer Join Date: Jun 2006 Location: 5150 Posts: 5,773	Floppys and HD require a bootblock and CDs require the .tm you can add it without the developers kit. I dont know is it just a file that is checked or is it actually part of the boot process like RDB? Commodore never licensed it - as far as I know it was free or with the developers CD you can make as many bootable disks as you like. the Floppy bootblock probably has copyright Commodore somewhere in it but it doesnt mean you neeeded a license. Last edited by Retro1234; 17 February 2016 at 22:19.

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17 February 2016, 22:48	#25
Amiga1992 Registered User Join Date: May 2001 Location: ? Posts: 19,645	You're utterly confused about this, and comparing a boot block with these files seemes like it was a bad example given your response, so I'll let anybody else explain it to you in a better way because I failed. To sum up, if the .TM files came with a developers license that you paid for, they are in NO WAY free. Acquiring a developers CD meant acquiring a developers license. And the stupidest part of this all is that today you can't go and acquire a dev license, so anyone making a fuss about it is just a tit.

17 February 2016, 22:59	#26
Retro1234 Phone Homer Join Date: Jun 2006 Location: 5150 Posts: 5,773	Ok Akira

17 February 2016, 23:43	#27
gulliver BoingBagged Join Date: Aug 2007 Location: The South of nowhere Age: 46 Posts: 2,358	Just build a custom trademark file and make it public so that this issue never happens again with the CD32. It is just a 2KB file for the CD32, I am sure we have plenty of coders that could help you on this.

18 February 2016, 09:49	#30
gulliver BoingBagged Join Date: Aug 2007 Location: The South of nowhere Age: 46 Posts: 2,358	Maybe it is just some sort of CD32.tm checksum, so if that is the case, the contens could be altered as long as the result of the operation remains the same.

18 February 2016, 11:35	#32
earok Registered User Join Date: Dec 2013 Location: Auckland Posts: 3,539	I would have presumed that a copy of the entire trademark was in the rom (the tm is only 2k) Having said that, I didn't spot a copy of it when I had a quick browse of it. If it is a checksum - surely we could bruteforce a matching trademark.

18 February 2016, 12:30	#33
Meshuggah 1200 gamer Join Date: Dec 2015 Location: Paris, France Age: 47 Posts: 34	The problem here is the content of the file I guess. There's a possible solution to this: if someone would forge a file that would trigger a buffer overflow in the reading routine, a payload inside the file could then be ran to circumvent the check. It's a long shot but maybe doable. That's only if a vulnerability exists in the reading routine tho

18 February 2016, 13:56	#35
SkulleateR Registered User Join Date: Jan 2016 Location: Germany Posts: 325	Btw. just had a look into cd32.tm and cdtv.tm .... cd32 file is exact 2KB and cdtv file is 22.152 Bytes ??? Are those the correct files (got it from developer kit) ???

18 February 2016, 14:00	#36
Meshuggah 1200 gamer Join Date: Dec 2015 Location: Paris, France Age: 47 Posts: 34	If it's using crc16 or crc32, it's possible to generate a different file with the same size and hash and be done with it.

18 February 2016, 14:05	#37
Retro1234 Phone Homer Join Date: Jun 2006 Location: 5150 Posts: 5,773	Yes thats correct CDTV.TM is bigger Ok thanks Meshuggah

18 February 2016, 14:07	#38
SkulleateR Registered User Join Date: Jan 2016 Location: Germany Posts: 325	Oh if someone wants to try : CD32.TM CRC32 -> E56C340F CDTV.TM CRC32 -> 37C532D7 As I said, these are those files from Developer Kit 2.1 Didn´t check files from any CD32/CDTV Disk yet

18 February 2016, 16:23	#39
Amiga1992 Registered User Join Date: May 2001 Location: ? Posts: 19,645	Great, I love where this conversation is going. I hope we can find an alternate and fuck the license vultures.

18 February 2016, 16:26	#40
Meshuggah 1200 gamer Join Date: Dec 2015 Location: Paris, France Age: 47 Posts: 34	Idealy, someone should trace the CD32 bios to check how the file is verified.

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