Hi David,
BTW, is there any DFU tool on linux?
You may want to check the repositories for your particular Linux distribution to see if they include a package for one of the DFU tools. When I searched for DFU on SuSE Linux (with some optional repositories enabled), I found 3 of them: dfuutil, dfu-util and dfutool.
I had no problems detecting the NanoVNA but did ran into a problem when I tried to flash the new firmware.
The NanoVNA has a different Device Id when it is in DFU mode then when it is in normal operation. The firmware file contains the Device Id for the NanoVNA in normal operation, but the NanoVNA must be in DFU mode for the firmware upgrade.
The DFU utility was comparing whether the Device Id in the specified firmware file was compatible with the Device Id on the command line and refused to upgrade because of a detected mismatch.
If the NanoVNA is the only DFU capable device connected to your computer then the easiest way to avoid the problem is to not specify any Device Id at all. Unfortunately I was not so lucky and on top of it, the offending DFU capable device with built-in and not easily removed.
The fix for me was to provide a partial (wildcard) Device Id. The Device Id consists of two values, the Vendor Id and the Product Id. Since the Vendor Id portion is the same when in DFU mode or normal mode, I specified only the Vendor Id on the command line.
As can be seen from the examples for NanoVNA firmware upgrades on Linux, this problem with the Device Id check does not apply to all versions of the DFU utilities/tools.
73,
Thomas
