"Please note: Starting with NanoVNA-H rev3.4 D2 uses IN4148, if your NanoVNA
D2 is a Schottky diode, use the "vbat_offset 150" command to calibrate the
battery voltage."
So it made me wonder if the rest of the software worked with earlier H
versions
The D2 story is: few nanoVNA were shipped with any D2 installed.
1N4148 was installed by some, Schottky by others.
Just as most nanoVNA (except gecko) have type C USB connectors
while few have the resistors necessary for type C connection.
The only significance of D2 is for accuracy of the battery gauge,
which can be corrected using that "vbat" USB shell command
in any firmware which supports the battery gauge icon.
Oristo