A2000 chipram upgrade

[Zac67]

As long as it's square PLCC Agnus, you can very easily upgrade the chip RAM to 1 MB. See this thread for compatibility info of the various 8375 models. Only the very early German A2000(A) Rev 4.0 can't be upgraded.

Once you got the 1 MB Agnus in place, switch J101 to 2-3 and open J500.
J101 remaps the $C00000 'ranger' mem to its original position at $080000 (just behind the first 512KB of chip RAM) and J500 open disables the (now mirrored) RAM at $C00000.

[Zac67]

According to BBoAH, 390544-01 is an A500+/A600 PAL Agnus for 2 MB - probably won't work in a 2000.  :-(

[Zac67]

Matt_H wrote:
8375 definitely won't work. You need an 8372(A) - ECS 1MB Agnus.

Not true, mate. Some 8375 are compatible with A500/2000s. In 1993 I got a bunch of them as spare parts directly from C=:
318069-16 PAL
318069-17 NTSC

[Zac67]

All 4.1+ boards have a full MB onboard.