Recovering from firmware update interruption?

[mwe-maxxowner]

Soooo. I recently sent my old mamba max (not pro) in for repair. I had an issue where the ESC would shut down, but I still had steering, then re arm, and carry on. They found no issues whatsoever, but did update the firmware.

When I got it back, I was in the process of reverting it back to 1.21 so that I can run 4s. I was performing the update with the rx cable adapter like the newer escs use.

See where this is going?

Well, if not, the older firmware versions don't support the rx adapter, and only work through the USB port built into the ESC. I never gave this a thought. Halfway through the firmware change, the connection was lost.

Now the computer won't recognize the ESC, and when I hook up power, I get a faint glow from the LEDs.

Is there any recovering from this mishap? Or cut my losses and appreciate the many years of service this outstanding ESC gave me?