Boy, it's been a long time since my A500, over 20 years. I seem to remember the dealer doing a mod. It consisted of a cut trace with a jumper wire. Some games would not work right and I had him return it to stock.
Yes, there was a basic mod you can do on the A500 if it was the right revision and if you had a the appropriate Agnus (1Mb) etc which would convert your 512Kb trapdoor RAM expansion to Chip RAM giving you 1Mb Chip. I helped a friend do it years ago after they bought an A590 and found they didn't have enough Chip RAM to do a number of tasks when using the hard drive.
