So I've given up trying to get my Fastlane Z3 scsi controller to work reliably with an Amiga 3000 with a buster 11. I find it so hard to believe that they don't work together, but sadly all I can do is use the Z3 for it's ram expansion (which works fine).
I did upgrade my Z3 eprom to the latest 8.5 version. If anyone has a Z3 fastlane with a lesser rom, I'd be happy to burn a new one and send it to them (no charge). I have a few eproms left over and hate to waste. Feel free to pass this offer along to others on other amiga forums.
If anyone knows of an amiga 3000 with a working fastlane, I'd be happy to learn of what magic is required.