Yes, most of them were RICOH... actually only now, after many years!, I have learned the difference... I guess my device is too old for these new 8x disks... A friend of mine has a not used burner that will give to me for a test, he doesn't remember the brand.
Yes, next time I'll take much more care of the real manufacturer...
Thank you for teaching me something new!
Ciao, Giangi