I was unable to install Endian ver 3.2.0_beta from CD neither on HP DC7800 SFF nor on HP DC 8200 SFF. The computers kept rebooting itself hardly displaying the first line of text from installation CD.
Then I tried to use the USB stick and the installator hang on "can't mount disk labeled "rec_boot", when I inserted a CD it continued and finished successfully.
When I was creating the image on USB stick, the refus.exe ver 2.7 complained about something being outdated on Endian iso image... (something ver 6.1 versus ver 6.3, don't remember exactly).
Hope this help.
Long story short: Use USB sitck and CD at the same time