This is beginning of Header file (1Mb) combined by 10 bytes
In offset 400h there is
SPOP word :) and image size in sectors on offset 406h (twice). The same that in offset
9368h in original CD image.
It seems that there is Country-Code Lockout for Japan consoles, right?
Emulator uses latest bios from SCPH-103 v4.5 J (there is no dump in community - so it will be useful not only for PS2) so it seems that it really use region protection.