Hello!
Am new to this forum but want to offer my experience with a couple of Mac Pluses and my SCSI2SD v5.0b - bottom line is that both boot absolutely fine from the SCSI2SD into a System 6.0.8 partition of 120Mb that I'd created using the cracked version of Apple HD Setup (the one that can be used with non-Apple disks). The Mac Plus systems boot up from the SCSI2SD in literally 10 seconds! As already covered above, I initially had a few problems which I thought it'd be useful to summarise the solution here:
1) SCSI2SD plugged in but not being recognised (e.g. by SCSI Probe). Symptom was that SCSI probe was saying the SCSI bus wasn't terminated, yet I had the resistor packs plugged into the SCSI2SD & lights on SCSI2SD don't blink.
Solution: ensure (as already noted above!) the SCSI2SD is powered through USB! I didn't have an enclosure, so providing CONTINUOUS power to the microUSB port worked a treat (I used a wall adaptor and USB-> microUSB cable). Powered, the SCSI2SD was recognised by SCSI Probe, and both Mac Pluses that I tried booted straight into the System 6.0.8 partition.
Don't bother with USB power banks, as I found that these power-down due to the low current draw from the SCSI2SD, and they do so at the worst time!
2) Ensure your Mac Plus has the latest v3 ROMs. This means that the "ROM-HI" chip should end in a C (it should be marked 342-0341-C), and the "ROM-LO" chip should end in a B (342-0342-B). The v3 ROM has the best implementation of SCSI for the Mac Plus (though it's still not perfect, hence the SCSI setting tweaks already mentioned:
- "Enable Unit Attention" should be OFF
- "SCSI Selection Delay" should be changed to 0 (mine was defaulting to 255)
- "Respond to short SCSI selection pulses" should be ENABLED
Not sure if the SCSI2SD works with v2 and v1 ROMs, but these should be quite rare as they are only likely to be in the earliest Mac Plus machines.
3) If you have multiple partitions / SCSI IDs (I had several with v7.5 and above, which aren't suitable for a 1Mb Mac Plus), then I recommend you use the SCSI2SD utility to disable all except your Mac Plus boot partition - at least until you've finished troubleshooting & have got a working setup.
As an aside, I'm also in the process of recapping the analogue boards of my 240v / International Mac Pluses, and have spent a few hours today to compile an up to date list of capacitor replacements (the previous Excel list from JDW was over 10 years old with a few parts no longer available, and it was for a 120v board where the capacitor listing didn't match). I'll post that separately in case anyone is interested...