Ubuntu Intel video card repository at 01.org requires a custom public key imported before you can proceed. The usual error method you will be getting is like this:

W: GPG error: https://download.01.org trusty InRelease: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY A902DDA375E52366

To fix this issue do the following:

sudo apt-key adv ––keyserver keyserver.ubuntu.com ––recv-keys A902DDA375E52366

 

Rember it’s dash-dash (––) in command line.

It should be fixed. For reference, I am including full log:

Executing: gpg –ignore-time-conflict –no-options –no-default-keyring –homedir /tmp/tmp.35JCw7DjiB –no-auto-check-trustdb –trust-model always –keyring /etc/apt/trusted.gpg –primary-keyring /etc/apt/trusted.gpg –keyserver keyserver.ubuntu.com –recv-keys A902DDA375E52366
gpg: requesting key 75E52366 from hkp server keyserver.ubuntu.com
gpg: key 75E52366: public key “Rodrigo Vivi (Intel Linux Graphics) <rodrigo.vivi@intel.com>” imported
gpg: Total number processed: 1
gpg:               imported: 1  (RSA: 1)