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NanoVNA V2Plus4 connects to NanovnaQT but not Nanovna-saver

PT 2021/05/05 19:46

NanoVNA V2Plus4, Windows 7 Home Premium SP1

I have installed the Cypress USB-Serial Drivers and rebooted my computer.

NanovnaQT (newest version 20200507 installed) sees the USB Serial Port (in my case Com5) and connects to the device no problem.  All is working fine.

I prefer to use nanovna-saver however (newest version 0.3.8 installed).

nanovna-saver does not see any Serial Ports - the selection dropdown is blank and hitting Rescan does nothing.  USB Serial Port Com5 is still showing in Device Manager

So - why does 'QT' see the Com Port and connect but 'saver' does not?

I know nanovna-saver is working because if I plug in my old NanoVNA-H, nanovna-saver sees the Serial Port (driver for that unit is STMicroelectronics and is using Com8 in my case) and connects no issues.


OK1VAW 2021/05/05 22:29

Hello Paul, I had the same as you, the reason was in my case the firmware in V2+4. After reflashing with new firmware (you can find it from OWo in the "you lost the game" the Nanovna works again.
it should be located on this link:
Vojtech, OK1VAW.

Barry - GM4TOE 2021/05/06 09:14

The solution is to update the firmware – 0w0 explained why some versions of Windoze don’t like a library element name in the current firmware.
Go to and install 20210425 experimental.
It certainly worked for my V2Plus 4 with nanoVNA-saver


PT 2021/05/06 14:56

Thanks very much to you both.  New experimental firmware 20210425 sorted it out :>)

fedorov.robert 2021/05/13 00:27

Thanks! Solution is confirmed for v2plus4. Win7 no SP1, nanovna-saver works fine with the 20210425, and does not see S-A-A-2 while device flashed by a stable 20201013. QT works well with both versions.

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