How do I get grub to recognize other boot devices?

[CremePuff]

How do I get grub to recognize my internal M.2 SSD as a boot device?

 

I have an Acer Aspire E15 E5 575 Notebook, not the best, but it gets the job done. I have three operating systems at this time; Windows 10, Ubuntu 18.04, and SteamOS. I have Windows and Ubuntu dual booted on a 1TB HDD, and SteamOS on an internal SSD. When I boot up my computer, I get a grub menu asking if I want to do one of four options: continue to Ubuntu, Advanced options for Ubuntu, Windows Boot Manager, and System Setup, but my SSD does not show up, neither does any other type of boot device. I can press F12 when my notebook boots to get to my systems boot menu; and SteamOS shows up there. But I'd like to know if there is another way to get my SSD to show in the grub menu.

[Ashleyyyy]

try this: 

boot into Ubuntu

open terminal

type: sudo update-grub

enter password

wait a bit for it to complete

reboot