Memory Configuration

For 1MB Chip RAM (A500+ default configuration):

• Install U32.
• Populate all RAM chips.
• Leave all jumpers to their default settings.

For 512K chip RAM (Mimics configuration of older A500 board revisions):

• Do NOT install U32.
• Cut the link between the middle and bottom pads of JP2 and put a blob of solder between the top and middle pads.
• Cut the horizontal links between the pads of JP3 and put two blobs of solder on them so that the connection goes vertically.
• Put a blob of solder on JP4A so that all the three pads are connected.
• Ditto for JP4B.
• Put a blob of solder on the middle and right pads of JP7A.
• Put RAM chips only in U20/21/22/23.

Information recovered from https://imgur.com/r/amiga/iTKBOaO.