Question about GVP A2000-HC+8 Series II - ROM, RAM Select...

[dalek]

You can get the v4.15 ROM here: http://babel.de/amiga.html
And the jumper settings here: http://amiga.resource.cx/exp/impact2000hc8

For: 8M [ 4M x 1 ]

Not sure, but I would guess you can get to 8MB normally by using 8x 1MB SIMMs.  If you only had 4MB SIMMs you could maybe populate 2 slots only to get 8MB and set the jumpers accordingly.

I don't think the usual 4M x 1 means megabits, rather megabytes (because of the same way M is used in 8M).