That's a very common prob I used to get...
After some time investigating that phenomen I discovered the first sector is corrupt, it happened whenever I patched with satconv a raw mode (2352) iso or bin, as my older burner doesn't correct the ecc codes on-the-fly... It can only burn 2352 tracks... (when burning mixed-mode discs).
Now the solution (if this is your prob) is to convert 2352 -> 2048 and patch it, then (if your burner requires it) 2048 -> 2352, and it's ready to burn.
Thus, as a general rule, I never patch raw mode ISOs...
In windows, these disc looked like *normal* coasters...
but I could play them on the saturn... read ahead..
This brings up another issue, the odd thing is that when I inserted the disc on the saturn, the lens tries to read the ring... that's VERY odd, as we *all* know saturn laser only goes for the ring when it assures it is a saturn disc, but if the IP.bin is missing...
I've discovered the first sector gets corrupted by using cdrwin's sector viewer, when I tried reading sector 00000, it gave me a reading error, but from 000001 to the end, it reads without any troubles.
Now... the game couldn't boot up using a modboard (gave me a "DISC Unsuitable ...", only by doing a swap, which means the IP.bin is read AFTER the protection... once again, we *all* knew that... now, how can saturn tell it is a saturn cd, without reading the ip.bin, as it tries to read the ring...
I still have some of those (bad) burned games... I can play them only using the swap...
It's 3.30am in here, i'm gonna sleep... this little discovery may be important...