To add to user Raffzahn's answer - this
It generates RAS/CAS signalling for each and every access, no matter what address is used (*1).
would imply that - talking about a system without any cartridges inserted - when a Program writes to the I/O area, for example some VIC or CIA hardware register, RAM memory in the $Dxxx area gets clobbered. Unless I'm ...
Another idea could be to dump some Kickstart ROM to a file, then either add a new Resident module if there is space available in the image, or overwrite a non-essential one (audio.device comes to mind, see below), with a custom module that calls Debug() on Exec (You could use the module's Init function to do this). Then you burn your new ROM to an EPROM and ...
This is intended to supplement the other answers here; you should also
read them if you've not done so already.
There are basically two possible situations when it comes to address
mapping and interaction with the cartridge.
If you assert G̅A̅M̅E̅ and do not assert E̅X̅R̅O̅M̅, there's only one
address mapping configuration possible because ...