I don't like the idea of restricted downloads, but have a look at this.
The latest BIOS in windows installer version is inside
cp028088.exe
Now google this and you are pointed to
https://downloads.linux.hpe.com/SDR/repo/spp/2016.10.0/hp/swpackages/
and you will find
http://downloads.linux.hpe.com/SDR/repo/spp/2016.10.0/hp/swpackages/cp028088.exe