Posted by: Dakusan
« on: September 24, 2019, 04:59:08 pm »Originally posted on: 09/24/19
I recently decided to swap around my hard drives to different SATA slots so my most used hard drives were on the fastest ports. Unfortunately, when I did this, my computer stopped booting to Windows. I never did figure out why my bootable EFI partitions only showed up randomly in BIOS depending on which hard drives were plugged in, but I found a configuration the computer liked and I was able to see the Microsoft Boot EFI partition and EFI boots on my USB keys.
The next step was to get the computer actually booting to something I could run commands on. When I try to boot directly to the EFI shell, the resolution is always screwed up and I can only see the top half of what should be visible, so I can’t actually see the command line I am typing too. This actually happens to everything I directly boot to that uses console text. The way around this for me is that I need to boot to the BIOS setup, and from there tell it to boot immediately to the EFI option of my choice when exiting the BIOS. From there, the proper resolution is used and everything is visible.
Next, in the EFI shell, you can run map to see all of the available possible mounts. This should automatically run when the EFI shell starts anyways, so you should already have that information. Any detected EFI partition on any bootable device should be given a mapping of “fs#” where # is a number. In my case, it was fs0. So to mount that, I ran mount fs0 x. “x” could be whatever you want, it doesn’t really matter. It’s analogous to a drive letter in windows, and you can make it any string (within reason, I believe anything alphanumeric should be fine). So next you would run x: to switch to that drive. From there, you can run cd EFI\Microsoft\Boot and then bootmgfw.efi to boot to windows.
Since I use VeraCrypt system encryption, I had to go to “EFI\VeraCrypt” and run DcsBoot.efi to finally boot into Windows through VeraCrypt.
Finally, to get the Windows Boot manager to start with VeraCrypt, run in the Windows command prompt bcdedit /set '{bootmgr}' path \EFI\VeraCrypt\DcsBoot.efi.
