* The first 8 physical roms can be accessed as lower roms. And all the 32 physical roms can be accessed as upper roms. A physical rom can even be mounted both as lower rom and upper rom at the same time.
* ROM boards are seen as logical roms. They can be accessed only as upper roms and there can be up to 128 logical roms.
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== Warning for ROM boards ==
On CPC 6128 and DDI-1, the internal ROM 7 can't be cleanly disabled (it works on some machines, but it means the internal ROM and the flash chip both use the memory bus at the same time, and it happens that the flash chip is stronger in this fight. But it could eventually damage the hardware).
On Plus and machines without disk drives, you can enable it.
ROM 0 can always be overloaded, but remember that you will not boot to the BASIC in that case ([[Hackit|the Hacker ROM]] is a popular replacement ROM 0, for example). [https://pulkomandy.github.io/shinra.github.io/gordon.html Source]
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[[Category:Programming]][[Category:Memory expansions]][[Category:Peripherals]][[Category:CPC Internal Components]]