Changes
/* 256KB RAM */
=== 256KB RAM ===
This uses 4 banks (effectively 0-3 on 464 and 2-3 on 6128). It appears the 256KB RAM detects the 6128, possibly using /EXP but this is to be confirmed, so that it doesn't conflict with the internal 'extra 64KB' (i.e. c4-c7) RAM of the 6128.
The decoding looks like this:
s = selection (0-7)
On 6128 you get 256KB RAM + internal 64KB base RAM
=== 256KB Silicon Disk ===
