The advantage of NanoVNA being open source is that people in the community are building software and firmware that are both feature rich and useful for the community of users. The NanoVNA uses STM32 micro controllers 32bit arm cortex MCUs. Loading a new firmware on the NanoVNA requires DfuSE software to load the DFU firmware available for download on the creator of the device Github pages, a quick search on google will let you download the software that we need to use in programming the NanoVNA device. I’ll put the software that I used here accessible on my Google Drive however it is advisable to get the files directly from NanoVNA creators pages as those are most up to date.
Steps in updating the firmware.
1. Prepare the NanoVNA to start in DFU mode.
2. Make sure that the device drivers are properly installed.
3. You need 1 open USB port for downloading the firmware on the NanoVNA.
4. Install DfuSE programming software.
5. You need access to the DFU firmware files.
Preparing the NanoVNA to start in DFU mode. I installed two pins on the the NanoVNA board marked as BOOT and VDD so I can easily short those pins with a clip or a twizzer to activate DFU mode.
Install the device drivers for the NanoVNA so that it can be detected by the DfuSE programming software.
When the device driver is not properly installed the software will not detect the NanoVNA.
A properly installed driver will enable the programming software to detect the NanoVNA device automatically.
Finally put the NanoVNA in DFU mode and start changing the NanoVNA firmware. Short the terminal marked as BOOT and VDD on the NanoVNA, connect the device on one empty USB port and turn on the device. This will activate DFU mode and the device is ready for programming.