Boot device not found after installing 18.04 dual boot

I’m pretty new to all this, so bear with me.

Trying to set up dual boot on my HP Spectre; more or less used this guide (https://itsfoss.com/install-ubuntu-1404-dual-boot-mode-windows-8-81-uefi/).

Now, I got the dreaded “Boot device not found” and hard drive 3F0 error.

Any tips?


https://www.ubackup.com/articles/hard-drive-not-found-3f0-error-8523.html


https://support.hp.com/us-en/document/c01443463/

Could you please try and see if similar steps as the ones below are applicable to you?