I have found a somewhat odd pattern and was hoping someone could explain it. I am running Ubuntu Gnome 16.04 from an external HDD on a Dell XPS 15 9560. It has both a NVIDIA GTX 1050 and Intel graphics. I have the current NVIDIA 381.22 driver for the NVIDIA card. When I am doing simple tasks, such as cruising the internet or whatever it may be, I like to switch to the Intel graphics for better power consumption. I do this either through the NVIDIA Driver by going into the prime profiles and selecting Intel, or through the terminal by:
sudo prime-select intel
Both yield the same result.
The issue occurs when I either turn off or reboot while still in the Intel prime configuration. When I select to boot into Ubuntu from grub, the boot always hangs. Instead, I need to boot into recovery mode and re-enable the Nvidia card.
The problem seems to be revolving around the Intel graphics. What is the best remedy for this situation, other than remembering to switch back to the NVIDIA before shutting down? Also, it should be noted that under the additional drivers tab of the software & updates window, the driver for the Intel unit is listed as "using processor micorcoce firmware for intel CPUs from intel-microcode"