I got my hands on an abandoned iMac 27" mid 2011, from the big garbage container. No keyboard or mouse in the box.
Former owner wrote nice note on box saying that: "gpu dead, but should otherwise work".
Quick inspection showed that harddrive is removed.

Turning on the iMac you can hear the fan starting. After a few seconds the fan goes to max speed.
Screen never turns on.

So what are my options to get Ubuntu (no macOS) running on this iMac?
  1. Can I install Ubuntu (from usb) and force iMac to run from integrated gpu (intel i915)?
    This depends if iMac will automatically boot from usb, if hdd is not registered and then ssh into Ubuntu to deactivate (blacklist?) 6770M.
  2. Will iMac boot and run if I install Nvidia Quadro 1000M MXM in it?
    Found a cheap one online.
  3. Other options?