Hello Friend.
I am trying to solve this problem with my Mining RIG, but I have a question ... Once I enter with root and then with the key (Simplemining sent it to my mail)
From there I do not know where to make the change that you specify, I mean:
Change GRUB_CMDLINE_LINUX_DEFAULT = "quiet" to GRUB_CMDLINE_LINUX_DEFAULT = "quiet pci = noaer" (this turns off Advance Error Reporting)

That part will not be done ... could you help me?