So is it possible to identify undumped ones by just looking at the mobo?

Yes, the "SC4309xx" names on the 52pin chips seem to be unique for each version/region. The older 80pin chips do probably also have some unique names (current rule-of-thumb is that 80pin chips aren't dumped, not matter of their name). The dev-board EPROM version http://upload.wikimedia.org/wikipedia/c … PU1_01.jpg has some sticker saying '94 11/28, that's also undumped, despite of the EPROM socket).

NB. when looking at the mainboards: It would be very nice to take photos/scans of their front & back sides. Such pictures are still quite hard to find in the internet.

The long answer is that the cdrom bios (or "drive firmware") controls this stuff: http://nocash.emubase.de/psx-spx.htm#cd … controller
PSX games are sending commands like ReadN, SetLoc, GetStat to the cdrom sub-cpu: http://nocash.emubase.de/psx-spx.htm#cd … andsummary Currently, PSX emulators are using high-level emulation to reproduce that commands, although nobody really knew what those commands were doing internally. Using low-level emulation for the 8bit CPU and the attached cdrom chipset should make emulators much more accurate...
But, in practice, most PSX games seem to be happy with high-level emulation either (I've emulated the whole stuff in no$psx last week (99% finished, but not yet released), and the overall effect was that it did make the the emulation slower, especially due to longer spin-up & sled-move times, but it didn't fix problems with game that did hang during cdrom loading - at least I do now know that those problems seem to be related to something else than cdrom emulation).

Rather not. The built-in dumping function is spitting out the whole binary in form of a "hexdump.txt" file, but I guess there's some copyright envolved nonetheless. Anyways, it's a pretty simple DIY project to dump it.

If somebody wants to send PSX mainboards to hamburg/germany, I could dump them for you (and return the boards... as long as I don't have to bother about the postage).

So is it possible to identify undumped ones by just looking at the mobo?
I don't have soldering equipment, but I might be able to send you some mobo's if I get them back in 1 piece (live near the German border).. Anyway, I guess you already dumped most PAL models that I have here.

Also, can you tell us what use these dumps will be? Can they help improve emulation?

Finally, are you planning to release the files? I see that MESS already added the decapped one: http://www.psxdev.net/forum/viewtopic.p … &t=431