I realize this may be a Windows 10 issue, but here goes.
I installed OpenSUSE LEAP 15.2 on my Dell Inspiron 7591 1TB SSD after using GParted to make space for it. GRUB2 did a good job booting the system (which has Secure Boot disabled in BIOS), so all seemed good.
Suddenly, possibly after a Windows update, GRUB2 would not load. I can boot off the install media and select More > Boot System, etc, and OpenSUSE isn't damaged. I've tried reinstalling GRUB2 like a dozen times. I've tried changing parameters by turning secure boot and trusted boot support on and off, telling update-bootloader to --reinit and write over files, looked around under /etc and various subfolders for any clue as to why it's doing this, but nothing seems to work.
The system uses /dev/nvme0n1 as the hard drive device name, with (weird) my MicroSD slot as sda. I made it a point to remove the MicroSD any time I try to reinstall Grub2 for fear it might think to use sda. Granted, I didn't own this MicroSD when I installed OpenSUSE LEAP 15.2, so I don't think it's getting "confused" by this device existing....
I have told Windows to boot into UEFI menu (which results in nothing happening on reboot). I have gone into the system BIOS and, sure enough, SecureBoot isn't even enabled.
I've tried installing GRUB2 with secure and trusted boot off, etc. I've basically "Christmas-treed" all the options on and off trying to reinstall GRUB2, to no avail.
I'm glad it boots Windows 10, because I need that for graduate school, but as we all know, OpenSUSE is better ;)
Does anyone know if there are advanced options in Windows or special flags in GRUB2 that I can use to force GRUB2 to not get "taken over" by Windows 10?
Also, GRUB2 has worked before, but I recall the warning message in the OpenSUSE installer about the EFI partition not being 256MB or whatever it says. Does that matter? Do I really need to boot back into GParted and move partitions around to resize EFI to be 256MB or higher? It's currently 150MB, but since GRUB2 has worked before, I would tend to believe that's not an issue, but am I wrong?
