I'm using RomCenter to analyze my Sega Master System ROMs.
There are two files it fails to correctly identify. I'm using the standard no-intro .dat, and the two files in question are "[BIOS] Hang-On (USA, Europe) (v3.4).sms" and "Sonic Spinball (Europe).sms". I have both of these files - and I've verified manually that the CRC, MD5, and SHA1 hashes for them all match exactly what appears in the .dat file. Regardless, RomCenter marks them as unknown in my files, and as missing in the database.