[Coco] Can't copy real floppy to CoCo-SDC on a CoCo 2

[mike at borncoco.com]

I re-flashed both the MCU and SDC-DOS. No dice. I still cannot use BACKUP between real floppies and CoCo-SDC on my CoCo 2. I'm stumped as to why.

DRIVE 0,OFF
DRIVE 1,OFF
BACKUP 0 TO 1

This runs successfully, but after the backup, SDC-DOS isn't there. The DRIVE command generates an "?SN ERROR". I also tried a backup from floppy 0 to an SD image mounted to drive 1. When I run this, it actually tries to write to floppy 1. Something isn't correct here. Any ideas Darren? I have two SDCs and they work OK in my CoCo 3, but they both have this issue in my CoCo 2. Its a puzzle.

I'm using a Tandy FD-501 controller, Disk basic 1.1 in that controller.

Oddly, this works fine:

DRIVE 0,OFF
DRIVE 1,"SDCSETUP.DSK"
BACKUP 1 TO 0

SDC-DOS remains working with DRIVE command working afterward. It shows DRIVE 0 is OFF and Drive 1 is mapped to "SDCSETUP.DSK" on my SD card.

However, I then try this:

BACKUP 0 TO 1

And instead of writing to "SDCSETUP.DSK that is mounted on drive 1, it actually does a successful backup to floppy drive 1, which should not be happening.

Once completed, SDC-DOS is gone and the "DRIVE" command returns a "?SN ERROR". So it seems like this might be a bug? Has anyone else been able to do this on a CoCo 2?

Thanks,
-Mike