help with files with (possibly) wrong checksums

This forum is for the discussion of dumping games. Get help with your dumping here.

Moderator: Moderators

kirk
Posts: 246
Joined: Wed Aug 20, 2008 9:22 pm

Post by kirk » Sun Aug 31, 2008 8:19 pm

Indeed, the GD-ROM assembly on both of my Dreamcasts appear to be made by Yamaha. They both have "YAMAHA" and "MADE IN JAPAN" stamped on them, as well as "610-6923-01" (apparently the model number).

Does anyone know if the newer Samsung GD-ROMs are compatible with the older Dreamcasts? Anyone with both models care to test it?
Quzar
Posts: 52
Joined: Mon Apr 23, 2007 1:22 pm
Location: Miami, FL
Contact:

Post by Quzar » Sun Aug 31, 2008 9:50 pm

Yea, I have a stack of them back home of both makes, but don't have access to them (and most are borked =P). I've used them interchangably before with no noticeable problem.
I only upload the information, not images.
kirk
Posts: 246
Joined: Wed Aug 20, 2008 9:22 pm

Post by kirk » Mon Sep 01, 2008 1:45 am

Hmm, well that's promising. However, it's probably much easier to just buy a new DC instead of trying to find a working Samsung-made GD-ROM. :(
User avatar
Maddog
is awesome
is awesome
Posts: 1509
Joined: Sat May 12, 2007 4:12 pm

Post by Maddog » Tue Sep 02, 2008 6:33 am

Ackmed ran a few test dumps with his Japanese Dreamcast, v5.07 GD-ROM BIOS as seen here.

He got same results, first data track had sync header of last sector bad (plus he had difficulty dumping the track anyway) and audio track had different offset. We got silly and didn't test with 3 data track game (he only did 2 data track game) to see what happens to track03 in this case, but I'll ask him to do that too. I'm almost certain it will have the same sync header problem though.

I guess we can safely assume this problem affects all old DCs with 5.06, 5.07 and 5.08 GD-ROM BIOSes. Still waiting to see if there are any further 5.xx BIOSes, with or without the problem.

@Quzar: thanks for the hardware info you provided
@Kirk: agree, it's probably easier to just buy a complete PAL or US Dreamcast with newer BIOS, instead of attempting to replace the GD-ROM unit only. Btw, were you able to dump track01 at first attempt, or your DCs needed several retries to do it, like ackmed's?

Ackmed is thinking of releasing an updated httpd-ack that will detect GD-ROM BIOS before dumping and display a warning if it discovers 5.xx BIOS. It might be a good idea IMHO, but we will probably try to get some further info before implementing it.
kirk
Posts: 246
Joined: Wed Aug 20, 2008 9:22 pm

Post by kirk » Tue Sep 02, 2008 11:25 pm

Maddog wrote: @Kirk: agree, it's probably easier to just buy a complete PAL or US Dreamcast with newer BIOS, instead of attempting to replace the GD-ROM unit only. Btw, were you able to dump track01 at first attempt, or your DCs needed several retries to do it, like ackmed's?
Actually both of my DCs appear to work fine, and don't seem to have any problems with ripping the discs I tried. It's really a shame about the apparent problems with Yamaha GD drives. :cry:
tobio
Posts: 6
Joined: Wed Jul 22, 2009 4:28 am
Location: UK

Post by tobio » Thu Jul 23, 2009 11:47 am

I've just set up my dreamcast to do some dumping and noticed the exact same problems. Mine too is an early HKT-3010 no modem dreamcast, and the test dumps I have done against disks that are in the DAT are the same as this post, i.e. track1 and 2 have different hashes and 3 is the same.

I own 17 games that aren't in the dat yet, mostly japanese, and can probably get hold of more, so im very eager to start submitting my hashes.

Does this mean that I can hexedit the tracks 1 and 2 and submit my hashes for consideration or do i need a new dreamcast?

Thanks
JAP Dreamcast + BBA
User avatar
Maddog
is awesome
is awesome
Posts: 1509
Joined: Sat May 12, 2007 4:12 pm

Post by Maddog » Sat Jul 25, 2009 4:18 pm

Hi Tobio.
By now we have determined that this problem affects all early firmware DCs and we know for sure what exactly is getting dumped badly. So, you don't really have to buy a new DC if you are confident you can do the needed steps to fix the problems with the dumps before submitting.
The only clause I have to put, is that your dumps will have to match dumps from known trusted dumpers (worry not, we have a few hundred unverified dumps waiting) and that if you hexedit something wrongly, I can't provide "target" CRCs to help you "fix" it. I can only point out something along the lines of "track XX seems bad".
On the other hand, if you decide to buy a new DC, we are virtually 100% sure that all PAL and USA models have the fixed firmware and therefore are not affected by this problem.

In any case, I will be happy to see some verifies from you. :)
Post Reply