psxbios: Some games read from address 0, fix that.
See Garbage Area at Address 00000000h in Nocash PSX Specifications for more inf>
R-types will refuse to boot if psxM[0] is zero.
Fade to Black can crash upon memory card access if psxM[5] is set to the wrong >
Crash Team Racing will refuse to boot if psxM[2] and psxM[3] are not zero.
(Previously, that region of memory would be overwritten above. No explanation why.)
It's set as such according to nocash :
[00000000h]=3C1A0000h ;<-- but overwritten by 00000003h after soon
[00000004h]=275A0C80h ;<-- or 275A0C50h (in older BIOS)
[00000008h]=03400008h
[0000000Ch]=00000000h
Note that setting 00000000h to 00000003h doesn't work for R-types.