ER101 Programmer 'failed to connect'. Update: resolved

I’m following the procedure as closely as possible. Downloaded the mono framework, etc.

Switching to USB while holding the reset button…and…nothing.

Tried on two different computers (both running Mojave) and two different cables. Advice?

I was trying this running Mojave on a couple different Macs, with no success. Tried it on an old Mac running 10.9.5 and that did the trick.