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Thread: Change installed system from GRUB to GRUB for EFI before upgrade to 15.1

  1. #11

    Default Re: Change installed system from GRUB to GRUB for EFI before upgrade to 15.1

    Quote Originally Posted by nrickert View Post
    what works depends mostly on your BIOS and how it starts the boot process.
    It sounds, then, like the problem is systemic. The BIOS options that I have available to me through the machine's BIOS management screens, as quoted in my previous post, say that the machine is using UEFI mode. If the lack of an efi firmware directory (/sys/firmware/efi) is not relevant, then is efibootmgr -v actually telling me that EFI variables are supported on this machine?

  2. #12
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    Default Re: Change installed system from GRUB to GRUB for EFI before upgrade to 15.1

    Quote Originally Posted by greggmoore View Post
    The BIOS options that I have available to me through the machine's BIOS management screens, as quoted in my previous post, say that the machine is using UEFI mode.
    Options that you described in your previous post simply say that if you boot in EFI mode you will have secure boot.
    If the lack of an efi firmware directory (/sys/firmware/efi) is not relevant, then is efibootmgr -v actually telling me that EFI variables are supported on this machine?
    If you have question about "efibootmgr -v" output then show this output. But lack of /sys/firmware/efi directory means that you are booted in Legacy BIOS mode, so efibootmgr is not going to work.

  3. #13
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    Default Re: Change installed system from GRUB to GRUB for EFI before upgrade to 15.1

    Quote Originally Posted by greggmoore View Post
    If the lack of an efi firmware directory (/sys/firmware/efi) is not relevant, then is efibootmgr -v actually telling me that EFI variables are supported on this machine?
    No. It is telling you that the kernel failed to communicate with the UEFI firmware, presumably because you did not boot with UEFI.
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  4. #14

    Default Re: Change installed system from GRUB to GRUB for EFI before upgrade to 15.1

    There seems to be something that you both assume that I know that I don't actually know, so: If setting both the machine's (ASUS UEFI) BIOS to "Windows UEFI mode" and the bootloader to "GRUB for EFI" isn't enough to cause EFI booting, then what is needed to cause it? There are no other options to set on the machine's BIOS nor can I see any other options in YaST beyond setting GRUB for EFI. What am I missing here?

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    Default Re: Change installed system from GRUB to GRUB for EFI before upgrade to 15.1

    I don't know the answer to that. Different BIOS behave differently.

    On my main desktop, I can hit F12 during boot. And it will give me a list of boot choices. Both UEFI boot choices and CSM (legacy) boot choices are there. If I plug in a USB that is bootable either way, I get to choose which way I want to boot it.

    On my other UEFI box (a Lenovo desktop), I can use F12. But it only lists UEFI boot options unless I make BIOS setting changes -- and then it only lists CSM boot options.

    Some BIOS look at the "pmbr_boot" flag and use that to decide how to boot. Maybe a web search for "pmbr_boot" will give some information about that.
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  6. #16

    Default Re: Change installed system from GRUB to GRUB for EFI before upgrade to 15.1

    Quote Originally Posted by nrickert View Post
    Maybe a web search for "pmbr_boot" will give some information about that.
    That may well be part of the problem. This https://www.suse.com/support/kb/doc/?id=7023923 from June 2019 (enterprise SuSE I know but maybe still relevant) suggests the flag needs to be set off. YaST leaves the flag as it found it, which on my system is On probably because it has been booting in legacy mode; YaST also suggests it be left alone unless one is an expert -- and you will have gathered that I am far from that -- so I had ignored that drop-down list.

    There is still the matter of the missing /sys/firmware/efi directory; is that not mandatory?

  7. #17
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    Default Re: Change installed system from GRUB to GRUB for EFI before upgrade to 15.1

    Quote Originally Posted by greggmoore View Post
    There is still the matter of the missing /sys/firmware/efi directory; is that not mandatory?
    What exactly you do not understand in "this directory appears only if Linux was booted in EFI mode. If this directory is not present, it indicates your system was booted in Legacy BIOS mode"? And indeed, pmbr_boot can well cause BIOS to not attempt EFI at all: https://bugzilla.opensuse.org/show_bug.cgi?id=932033

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    Default Re: Change installed system from GRUB to GRUB for EFI before upgrade to 15.1

    Quote Originally Posted by greggmoore View Post
    There is still the matter of the missing /sys/firmware/efi directory; is that not mandatory?
    That is a logical thing, not a physical thing. It is created by the kernel when it finds that it was booted in EFI mode and is able to communicate with the EFI firmware.
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    Default Re: Change installed system from GRUB to GRUB for EFI before upgrade to 15.1

    Quote Originally Posted by greggmoore View Post
    There seems to be something that you both assume that I know that I don't actually know, so: If setting both the machine's (ASUS UEFI) BIOS to "Windows UEFI mode" and the bootloader to "GRUB for EFI" isn't enough to cause EFI booting, then what is needed to cause it? There are no other options to set on the machine's BIOS nor can I see any other options in YaST beyond setting GRUB for EFI. What am I missing here?
    You may consider running a live system in UEFI mode, which is a great way to check your machine: https://en.opensuse.org/How_To_Try_o...ges_To_Your_PC
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  10. #20
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    Default Re: Change installed system from GRUB to GRUB for EFI before upgrade to 15.1

    Quote Originally Posted by greggmoore View Post
    There seems to be something that you both assume that I know that I don't actually know, so
    That is of course quite possible and I think that reading this discussion I detected one. Unless you now understand from @avidjaar and @nrickerts posts above, it is that /sys (same for /dev and /proc) is a file system (of a special type) created only by the kernel at boot and existing only as long as a Linux system is running.:
    Code:
    boven:~ # mount | grep '/sys '
    sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
    boven:~ #
    That means you can not find it's contents in an unused / file system. of a not booted Linux.

    You will now understand that neither a person, nor the BIOS at boot time, nor Grub can ever have anything to do with it before a Linux kernel is loaded. And that what is in it can only point to what happened during boot and not to what should happen.
    Last edited by hcvv; 16-Oct-2019 at 01:15.
    Henk van Velden

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