Well... I got:
Found empeg unit: entering program mode
Manufacturer=0089, product=88c1
starting erase [Bad result code: 0xa2

That doesn't sound good.

That just sounds like it had a comms error. Still on MS-Win, eh?

Ok. No, this was download.c on Linux Mint.

I'll see about ordering a new null cable.

The cable appears to be working. It could just be perhaps needing a different chipset in the USB-Serial Adapter.

What does 'lsusb' show for the adapter?
If I have a similar one here, I could re-test against it.

Cheers

Nope. That's not it. New null-modem cable does the same thing. It gets about 16-20% through the erase and throws that error. Any other ideas?

This is via a 9-pin to the 9-pin on the empeg.

Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 0040:073d
Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Is that what is reported for ttyS0?

dmesg shows:
[ 0.563684] 00:03: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A

Changed to stty -F /dev/ttyS0 cs8 -parenb -cstopb and tried again.
Still [Bad result code: 0xa2