I'm a very happy owner of an Airspy HF+. It's one of the best SDR receivers I have used in my remote RX site. I use it now connected to a RPI3 running Raspbian and spyserver software.
I have successfully updated many times the airspy HF+ firmware remotely and even performed remote recalibrations, flashing it into the device (Using the frequency standard stations at 14.996 and 9.996 Mhz). For this I have used the free USB server and client from http://www.virtualhere.com.
1- If you perform this remote flashing "the Airspy calibration is lost!!". If you can't bear it or you are not comfortable with a recalibration, don't try it!!.
2- Possibly you need a very good data bandwidth and low network latency between local an remote, my link is really good in these respects.
3- Remote raspberry PI3 and local computers need to be in the same broadcast segment (same network) as the USB server/client software uses discovery. If not, you can setup a VPN between the two sites.
It's supposed you are comfortable with Linux, networking, etc. If not, don' try it and wait for the next trip to the remote.
A- Download USB server for Raspberry PI from http://www.virtualhere.com and follow the instructions to install and execute it. Turn off the spyserver software. Execute the virtualhere soft (as root or sudo).
On the local side (windows 10 in my case) Install the client and run it. I will soon discover the RPI USB and show all the devices connected. Right mouse button allows to virtually connect to it.
B. Execute the FLASH.bat file from the firmware kit, it erases the device and reboots in flash mode. After rebooting the SDR,It stops flashing because it can`t find the device!.
In the USB virtualhere client you can see a new device labeled 0x6124 for the device:
you must connect to this new usb device and restart the flashing procedure. Maybe you need to make this a third time. If successfull:
C- Powercyle the rpi+airspy and possibly you have the new firmware installed and working successfully.
D- Calibrate the SDR with the SDR# if you have enough Data bandwidth for the operation. If not, you can put the value in the spyserver config file (read elsewhere in the forum).
note: Of course, even if you successfully flash the new firmware it is not possible to to use the new manual settings in the SDR# in spyserver/client mode.
The airspy HF+ with the latest firmware and SDR# is an incredible receiver!! and needs not any manual settings in my setup.
Congrats on this clever SDR design, firmwares and software. It's the best value for money SDR nowadays, in my opinion.
Best 73 all