I will try that network setting and will report back.

I used Rufus to 'burn' the image onto two SD cards using Windows 10. Both cards were used successfully in six other S9/S9i units (13.5TH and 14TH variants). I re-burned one of the SD cards today using Rufus again to rule out possible corruption. I also made sure the SD card slot was cleaned out well using compressed air.

I am really beginning to wonder if I am up against the security checks in the newer Bitmain firmware. These units are running Antminer firmware from June or July 2019.