is it possible to use debian with mini PC when display is not connected to hdmi

["Mgr. Janusz Chmiel" <mgr.janusz.chmiel@gmail.com>]

Dear users and developers,
    I would like to know, if is it possible to use Debian Mate on mini 
PC with 8 GB of RAM if I will not use external monitor connected to 
provided HDMI output connector.
Does build in firmware written in Assembly allow Me to simply boot The 
Debian kernel if The display will not be connected?
Or unfortunately, firmware will recognize this fact automatically and 
will not allow me to load GRUB and boot The kernel:?
I do not see at all so I want to use 20 Watts energy comsumption with no 
need to use external monitor.
It is possible on Raspbery but I Am afraid, that mini PCS firmwares will 
not allow Me to boot The system at all.
What do you think?
Thank you very much for your answer.