Flashing new Coral Dev Board 4GB

Noting the Coral Dev Board release has been updated I tried to flash with v2.108.26 with:
• Coral Dev Board 4GB
• Development, Wifi + Ethernet, no advanced settings.
• Board switches set to boot mode, as per Google Coral documentation, on-off-on-on.
Using RPi as host connected to terminal no activity other than slow advance of terminal window.
Tried with a 64GB card and then a 16GB card, same.
Any thoughts what could be wrong?

Update: Another person with the 1GB RAM/8 GB eMMC has used this version of the OS successfully. I have the 4 GB/16 GB eMMC version.