Using hptc-bios-flash on TC T620

I am trying to update the BIOS on a Thin Client T620 (HP ThinPro 6-64) from 2.08 to 2.11 and I am having issues with hptc-bios-flash.  I get the following message.

"The version of BIOS on thie thin client may not support tool-less BIOS update"

I then get a message to reboot, but the BIOS remains the same.  As a test, I was able to update the BIOS on a different T620 with ThinPro Version 5. 

Does anyone have any suggestions?

Thanks.