I decided yesterday to update the firmware in my nanoVNA-H. I haven't done this before and the version in my device was from December 2019.
Time to stop procrastinating.
I downloaded DefuSE, the program that performs the update, and also the firmware itself.
With everything in place and connected, I navigated DefuSe to the firmware's location on my PC and hit the UPDATE button.
All looked good and I got the green "Verified" light at the end. The last step was to power cycle the nanoVNA and start enjoying the capabilities provided by the new firmware.
But all I got was a white screen.
Turns out the nanoVNA accepts a different firmware format than the nanoVNA-H and -H4.
Each version is offered with a .hex, .bin and .dfu extension. I needed the .dfu; the hex and bin extensions are only for the nanoVNA (not the -H varieties).
The recovery operation was done by powering up the nanoVNA-H with two pins (boot0) on the circuit board shorted. This places the nanoVNA into DFU mode even though there is no indication of this.
Then the correct format of the firmware was loaded and all was well.
I should have watched this from W2AEW: