On Tue, Feb 27, 2018 at 09:01:18PM -0500, Dan Norton wrote: > Why insert itself anywhere in the first place? The machine booted > before the installation. To start installing, the installation medium > is placed in a CD drive or USB port and the machine is rebooted. During > installation, other OSs are detected by the installer. The installer > forms the grub menu with the latest install first and the other OSs > following. Installer finishes by reminding the admin to remove the > installation medium and it reboots the machine. The latest install > boots unless the admin intervenes. Where in this process is a > requirement to tinker with the UEFI menu?
How are you supposed to get grub to run at all if you don't add a boot entry for it? The grub is installed by this installer after. There is nothing that makes the latest install boot unless you add it to the boot order. On legacy bios it was different because there you just put what you wanted into the MBR boot sector and the BIOS was typically configured to boot from the harddisk. UEFI does not work that way. UEFI uses an explicit entry specifying which filename to boot from which harddisk. So an entry is created specifying to boot the grub_x64.efi file from the FAT partition containing the bootloaders. Now there are some default filenames that UEFI will look for if not explicitly told, but they are not always supported and most installers don't use those filenames because it isn't reliable, and the explicit entry is the official way to do it. The installer has no way to tell what else was on your system already and how it booted. -- Len Sorensen
