Changes

Internal Upgrade of the CPC 6128's internal RAM to 512 KiB as proposed in the article '''Aus David wird Goliath: 512 KB RAM expansion for CPC6128 from german magazine für Schneider CPC'''c't, in issue 10/1987, pages 156 to 162 of the German IT magazine '''c't'''. The DIY project name is '''CPC 6512'''. The mod requires to remove (or disable) the sixteen RAM chips on the CPC6128 mainboard, and to replace them by bigger chips, plus whatever additional bank selection logic.