I have a Dell Insprion N5110. It usually comes with a HDD, but I replaced the Optical Drive with a SSD. Now I have two drives and I am trying to install Windows 10 and Ubuntu 16.04 in a dual-boot configuration.
The problem is that my primary drive is the HDD and the secondary is the SSD and my laptop has only the two boot options "Hard Drive" and "Optical Drive". (I am not sure if "Optical Drive" now means "SSD" and I do not know how to test that either.)
I installed Windows on the secondary drive (the SSD), but it also created a 500MB system partition on the first drive (the HDD). There is no way I can change that and I decided to live with it. After that, I installed Ubuntu and it asked me where I want to install GRUB. Because there was the system partition on the first drive already, I decided to also install GRUB on the first drive.
Now, to get to the issue: when I start up my laptop, it should boot from "Hard Drive" because that is the 1st boot option in BIOS. It does boot GRUB, says that "no such device was found SOME_LONG_ID" and continues with GRUB rescue (the command-line). If, when the laptop starts up, I choose "Hard Drive" from the Boot menu, it works fine and loads GRUB correctly.
What could be the issue? How can I make the laptop boot GRUB on start-up? Could there be a "stray" GRUB installation from my previous tries?
Also, I dumped the MBR records of both drives. The first drive seems to have GRUB there, but the second one has something else I do not recognise.