A500 GVP HD+ Memory Expansion Issues

[Motormouth]

Mmmm.  Other than Jumper 2 for the 1 meg chip ram mod, what else has been done? any mods to the Gary?

is your mod something like this
http://www.boobip.com/hardware/A500_2MB

if so you may need to try removing the gary adapter and put the trapdoor ram back in.  The 2MB trapdoor expansion will act like it is 0.5 meg expansion (the gary will not know anything else is there)

The fast ram in the GVP will be accessed rather than the slow ram (mapped as fast ram) in the trapdoor.

Just FYI the GVP fast ram should be faster than trapdoor slow ram mounted as fast ram) anyway.

[Motormouth]

Sorry
To be specific about this
The one meg chip mod should be on the A500 motherboard itself near the 68000, jumper 2
https://www.amibay.com/threads/a500-r6a-1mb-chip-ram-modification-caution-dialup-users-excessive-h-w-pr0n.4984/
This allows 0.5 the regular slow memory to be to added to the 0.5 meg on board to get 1 meg chip.
up to $0FFFFF
http://amigadev.elowar.com/read/ADCD_2.1/Hardware_Manual_guide/node00D3.html

As for the gary adapter, I am wondering if it allowing some of the trap door ram to added to the 8 meg auto config space
ie $200000 - 9FFFFF    8 MB Auto-config space

you could check this with sysinfo or another utility.

FYI slow-fast ram is usually mapped at  $C00000

It might be useful to look your ram mapping.

Regular Fast Ram (ie the GVP HD8 ram goes to the 8 MB auto-config space)

I have an GVP HD8 on my main A500, and an IDE Ad540 on one of my other A500s (which is a large trapdoor memory expansion with a gary mod plug in)
However your trapdoor expansion might be different which is why I would look at the address space with sysinfo