ACA500+ Firmware 0.135 - $C0/Trapdoor RAM menu item is disregarded, ranger memory is always on.

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Don't Panic. Please wash hands.
  • Hello!


    In the expert menu, regardless of the setting for $C0/Trapdoor RAM being on or off, the memory is always enabled and so never gets turned off. This is particularly prominent on an A500+ with no trapdoor expansion.


    On a rev 6 A500 with an A501, if the chipmem 1MB item is enabled then the $C0 memory is always turned on regardless of menu item once again. I assumed this was owing to how the trapdoor was turned into chipmem but it seems to be related to the same issue I'm seeing on the A500+/rev 8.


    Is there a dependent menu item which is forcibly turned on which I can use to fix this issue?


    Thank you in advance for any advice.

  • As you can see here, the trick of making sure that trapdoor memory is not seen is that the ACA500plus mirrors $c8-$d0 on $c0 memory. The best explanation I have is that there is a 1.8M memory expansion in the computer, so that re-mapping, which *should* move a mirror of chip registers into trapdoor area, does not work.


    Just for verification of your hardware revision, what's the warranty ID of your ACA500plus?

  • The last reply was more than 365 days ago, this thread is most likely obsolete. It is recommended to create a new thread instead.