GC Creating bootable mini DVDs... possible?

[FamilyGuy]

That article was a bit weird. They say the AR disc doesn't have a BCA, but that doesn't really make sense. Unless they mean you don't need to *burn* a BCA and instead could embed it in the disc like you would to get around the mark/hole part? This then suggests you could just have a special iso you burn to a Mini-DVD-R and it works, but obviously that's not the case so idk how valid that source is.

The BCA is perceived by the drive as invalid EFM data. Datel realised that they could simply write the data that the drive perceives in order to trick it. Basically they found a way to write normal data that'd be indistinguishable from the BCA for the optical drive, hence the copy protection is defeated.

But I don't think it'd be easy to write that data on a blank disc using a consumer burner, even though no YAG laser is required thanks to Datel.
Maybe a custom firmware or an Arduino driving the laser could do it though.

[EDIT]
I had forgotten this topic completely, but reading back, it boils down to those two quotes.

Link says they use the bca area. You can't write this, only press.

So while it may be possible to make your own pressed disc that boots, you arent making a dvdr that does.

The header of each Datel disc contains the game identifier of NHL Hitz 20-02 (if I remember correctly). Datel disc are very weirdly mastered - there are fragments of valid PSN (physical sector number) blocks, but it's not continuous. I.e. it's hard to rip the game without losing information _even_ when you capture the raw EFM+ bit stream, because apparently the spiral has discontinuities. (I need to do some more SEM imaging, this should be visible).

The idea at some point was that Datel hat stitched together part of an original game with part of their data. In theory they may have kept the original BCA intact, and duplicated the stripe position by embedding it into the bitstream. All(?) Datel discs use the same BCA.

This is interesting because if you can keep the BCA and relative stripe position, you don't need to re-encode the BCA, and you don't need to understand the encryption algorithm of the BCA. (Remember that the relative position of the stripes to the data is stored encrypted in the BCA; (un)fortunately with a symmetric cipher). So maybe Datel didn't understand the encryption?

At some point a friend bought a pressed US version of that game, and I dumped the EFM+ bitstream of that disc, and compared it with the Datel disc. Result: it was different. So either I took the wrong NHL Hitz version/region/whatever, or Datel did indeed remaster the disc.

FamilyGuy - yes, "afte encoding" == illegal EFM+ / flat 0 zone. (Strictly speaking there's a physical different between BCA/Stripe and flat-zero, but the reader isn't able to see the difference).

My setup is a modified DVD burner where I interface the LVDS channel that drives the laser diode with an FPGA. It worked to a certain extent, but never well enough. I was able to write arbitrary EFM+ bitstreams to disc, including lightscribe-style disc art and fake-BCAs. It's more than a firmware hack, but everything non-digital is still the original burner. Writing wobble is not directly possible, but with a crude hack (feeding an AC signal into tracking coils while writing...) it may (or may not) be possible.

In summary, most frustrating project I've ever worked on. (If someone could find me the source code for a DVD or BD writer firmware, I'd be _sooooo_ happy.)

 

[Protofall]

[cut]

"(If someone could find me the source code for a DVD or BD writer firmware, I'd be _sooooo_ happy.)" - tmbinc

Maybe that's the next step. Find a DVD Burner's source code for better accuracy. I assume he means the burner and not writer software such as ImgBurn (Which is open source I believe).

Now where could you even find something like a DVD burner's source code and even then we'd probably need a specific DVD burner (I assume the source code is specific to the drive model it came from)?

 

[Protofall]

Ok, so I found 3 github repos that look somewhat promising for DVD burner firmware stuff. The first, and least promising, one is an arduino program that seems to more so be using a DVD drive to draw stuff. The second one is a firmware writer/dumper for NEC and Optiarc drives. I don't really know what the third one is. There's no readme and the repo is rather young (Started Sep 2019). It does involve dvd firmware apparently so could be useful.

@tmbinc are any of these useful for getting better results? Or do you need the source code for their comments/readability?