[hpsdr] Boot loader for DFC Firmware

[ad0es]

Hi,

I need to load DFC based FPGA firmware  that Phil is building for me to 
my anan200D .

It comes with the caution:

The FPGA code does not presently provide a facility to load new versions 
of code.
In which case to load new version of code, or revert to a previous version,
Bootloader mode will be required.

What/where is the appropriate boot loader program to accomplish this?  
It has to run on Ubuntu 16.04LTS.

I can build from source if available (and would prefer to).

tia,

-- Steve AD0ES