My ESET antivirus triggers on that link....

Probably because of an ad on that file hosting page. There is no way a 7z archive or firmware file could possibly harm you - except when doing a bad flash...

If it bothers you I can send the firmware in a pm.

No problem, I'll do it later at home from Linux.

I re-uploaded rosewood file in Mediafire

http://www.mediafire.com/download/ahu4v7j2avxagmo/a278308.7z

Thanks for the dump. It's a strange ROM type so it's maybe bad? I doubt it's encrypted and there's normally some kind of plain text readable either directly or with a bit-swap with the manufacturer's name or a date or version number.
Since there's none of that it could be bad.
To figure it out will require tracing the PCB.

Regardless, even if it's good, the NUON dump is incomplete.
There's also an Atmel AT49BV1614 smd flash ROM in the lower left corner of the PCB.
you'll need to dump it before we could add emulation or a basic skeleton driver to MAME.
or send it to someone who can dump it and guarantee it'll work afterwards (i.e. me ;-)

Traces of plain text or dates was the first thing I was looking for too. But the size is ok and there are some repeating patterns, so I came to the conclusion that it's not just a bunch of garbage but encrypted, or something is missing.
I noticed that all the chips are grouped together by naming. The A278308-90 is called "MIC2" and the TMP91C219F next to it is "MIC1". The whole NUON part is NICx, e.g. the Aries-3 being "NIC1" and the Atmel flash "NIC11". There is also VICx, PWICx, RICx, SICx...

Unfortunately my programmer doesn't accept TSOP48 Atmel chips, so I guess it's best to send it to you. What do you need, just the two chips or something else from the PCB?

Here's another Nuon firmware update - probably a patcher, not the full firmware - for the Toshiba SD-2300: http://www.nuon-dome.com/sd2300firmware.html
More info and photo of disk: http://www.nuon-dome.com/demos/toshupdate.html

Owner's Manual for the Toshiba SD-2300: http://www.videogameconsolelibrary.com/images/Manuals/00_NUON_Toshiba_SD_2300-1-Manual.pdf
Service Manual for the Toshiba SD-2300: http://www.videogameconsolelibrary.com/images/Manuals/00_NUON_Toshiba_SD_2300-2-Manual.pdf

As for the Samsung DVD-N501 update mentioned 2.5 years ago and a page or two ago: http://www.nuon-dome.com/n501firmware.html
there was apparently a newer version released, "nuon52.zip":
http://web.archive.org/web/20020808141709/http://www.samsungelectronics.com:80/dvdp/nuon/n501.html
So far, haven't found anyone who archived it.

Samsung DVD-N501 owner's manual: http://www.videogameconsolelibrary.com/images/Manuals/00_NUON_Samsung_N501_manual.pdf
Samsung DVD-N501 owner's manual - mirror: https://archive.org/details/Samsung_DVD_Player_DVD-N501_1999_U
Samsung DVD-N501 service manual: https://elektrotanya.com/samsung_dvd-n501_sm.pdf/download.html

Samsung DVD-N2000 owner's manual: http://www.videogameconsolelibrary.com/images/Manuals/00_NUON_Samsung_N2000_manual.pdf
Samsung DVD-N2000 owner's manual - mirror: https://archive.org/details/Samsung_DVD_Player_DVD-N2000_2000_U
Samsung DVD-N2000 service manual: https://elektrotanya.com/samsung_dvd-n2000.pdf/download.html

Those service manuals are useful. The N501 has a TMP91C219F main CPU; the firmware is for that CPU. The Nuon's firmware apparently isn't upgradable; it's stored in the flash chip that couldn't be dumped.

right, sounds like we need to get one to somebody on the DU who can try various things with it then?