Re: Problem with Grub
David Wright composed on 2021-06-22 11:00 (UTC-0500):
> On Sat 19 Jun 2021 at 14:51:53 (-0400), Felix Miata wrote:
>> As already mentioned, you needn't have paid. Two unrelated things were likely to
>> have caused this to happen. Vista and or Win10 could have been installed in MBR
>> mode, which is compatible with having Grub on the MBR, but the failure could have
>> been that os-prober was either not installed or not configured to include any menu
>> option for Windows.
> Would I be right in assuming that you could still manually boot
> Windows at this point by using Grub's command line, along the
> following lines:
> GRUB> insmod fat
> GRUB> set root=(hd0,gpt1)
> GRUB> chainloader (${root})/efi/Microsoft/Boot/bootmgfw.efi
> GRUB> boot
> (That's the sequence I used when I had to do this myself, and
> I originally navigated my way there by means of Grub's TAB
> command-completion.)
Sure. Grub menus are scripts that call some of the same commands available while
at a Grub shell prompt.
>> The other likely failure mode could have been that either Windows could have been
>> installed in UEFI mode, while Debian was installed in legacy (MBR) mode. All
>> installed operating systems on UEFI PCs need to be installed in the same mode to
>> permit Grub to be able to boot all of them.
> Presumably if they had managed to install Debian/BIOS on a
> Windows/UEFI computer, then they ought to be able to switch between
> these modes at will. That's how I installed Debian on a machine where
> my wife still needed to be able to boot Windows. (No chance of being
> permitted to alter the booting scheme while that need remained.)
Technically it's /not/ needed for all to be in same mode, but /when/ not, and
presuming firmware competence, navigating the PC firmware to some extent is
required for each instance of need to boot an OS that has been installed to
another mode. The "need" has to do with using installed software, usually Grub on
x86 compatible hardware on which Gnu/Linux has been installed, to select which OS
to boot. Hence, the "need" applies in a Grub in maximum control context.
--
Evolution as taught in public schools is, like religion,
based on faith, not based on science.
Team OS/2 ** Reg. Linux User #211409 ** a11y rocks!
Felix Miata
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