Cannot update firmware on new NanoVNA-H4

[JS2OLO]

Hello,

My new NanoVNA-H4 arrived today.  I immediately set out to update its firmware to the latest version (v1.2.29) but have been unable to get the DFuSe_Demo_V3.0.6 bootloader to "Choose" the DFU file (NanoVNA.H4.v1.2.29).  I get a "This file doesn't have a correct format..." error every time I make the attempt.  I therefore cannot update the firmware in my new NanoVNA. 

How can I fix this problem?

See attached screenshot.

Thank you,

JS2OLO

[Peter BENSCH]

See my answer here.

Regards
/Peter