Charles has gone a bit quiet on this :-( - thought he was going to storm all the Hitachi stuff in a day or something ;-)

But it is interesting what he found about the 4xxx type opcodes. Here's a quick example. I don't know if these are the same but they could be. This is Thunderblade Japan (j) and Thunderblade Custom/USA (u)

Notice the 4e75 <==> 0e75, 4eb9 <==> 0eb9 bits, that's what Charles was talking about I think. Should really put a disassmbly on this as well for more clarity on what is data.

j    0: ffff ff00 0000 0404 0000 0400 0000 0400 
u    0: 3347 f299 8301 abde 0000 0402 0000 0400 
     
j   60: 0000 0400 0000 0400 0000 0d60 0000 0400 
u   60: 0000 0400 0000 0400 0000 0d4e 0000 0400 
j   70: 0000 0b28 0000 0400 0000 0400 0000 0400 
u   70: 0000 0b16 0000 0400 0000 0400 0000 0400 

j  6b0: 4e75 13fc 0004 0029 c006 08f8 0001 8112 
u  6b4: 0e75 cb5d 8bfa 222c d993 ab3c e6a3 537d
         /\
j  6c0: 4eb9 0001 7d04 4e75 2e7c ffff ff00 13fc 
u       0eb9 92c8 1aa8 0e75 efea 9687 ce75 52e0
         /\             /\
j  6d0: 0008 0029 c006 08b8 0000 8118 46fc 2100 
        33e7 23a7 8c95 8a65 3f23 d12d 06fc fe58
                                       /\