512K RAM Expansion - Schematics?

[beaker]

  Offense duly taken, it seems a shame to discount the original 2 iterations of the machine 

Only kidding, if it's too much work to implement then it's probably not worth the hassle, I mean it is more of a hobby these days rather than a viable commercial venture (no one will get rich over it). I've got the 6128 and 6128 plus along with the 464 and 64k RAM so I have my bases covered.

Out of interest, is the RAM in the Symbiface2  fully compatible with the CPC 464?

[TotO]

Out of interest, is the RAM in the Symbiface2  fully compatible with the CPC 464?

Absolutely not.