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Thread: UEFI / grub / "ubuntu" small issues

  1. #1
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    UEFI / grub / "ubuntu" small issues

    Perhaps somebody could be re-educate this group , me included , how it all fits together.
    ( It has been an ":issue" since I first loaded Ubuntu...)

    so here is my view , no particular sequence , just my opinions:
    1. There is no BIOS
    2. Instead of BIOS there is so0mting called UEFI / EFI (?) - or "hardware setup."
    3. Initially my hardware came with "default EFI"
    4. Part of the EFI is "boot sequence " - NOT BIOS!
    5. After initial Ubuntu install my "default" boot sequence was titled "Ubuntu" ?
    6. After my :setup" is done I get to see "grub" which would NOT be seen if I had SINGLE boot system!
    7. I can select actual 'boot" process / OS in "grub" or let it process the mystery "Ubuntu " - as optioned in my "UEFI" setup.

    As far as i know - there should be ONLY ONE grub file in the system and putting in on USB should be fine.

  2. #2
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    UEFI / grub / "ubuntu" small issues

    UEFI has a default menu entry and even old BIOS had a default on which drive you could boot from.
    To see boot order with UEFI:
    sudo efibootmgr -v

    Grub has a default boot entry and if only one install, will not normally show menu, just boot that one entry. You have to press escape key just after UEFI/BIOS screen but before grub. If UEFI fast boot on, you may not have time to press a key and have to do a "cold" boot or full power shutdown.

    UEFI currently has CSM, but future proposals discuss eliminating CSM on new systems.
    CSM - UEFI Compatibility Support Module (CSM), which emulates a BIOS mode, only available with secure boot off.

    When Apple converted to Intel chips, it also used Intel's EFI. Then Intel turned EFI over to a separate group and it was UEFI v2 and old EFI became v1.
    Microsoft required vendors to install Windows 8 in UEFI boot mode to gpt partitioned drives in 2012. So most hardware is UEFI based.

    Lots more info & links to details at end of my post linked below in my signature.
    Last edited by oldfred; October 5th, 2020 at 06:33 PM.
    For more info on UEFI boot install & repair - Regularly Updated :
    http://ubuntuforums.org/showthread.php?t=2147295
    Please use Thread Tools above first post to change to [Solved] when/if answered completely.

  3. #3
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    UEFI / grub / "ubuntu" small issues

    While troubleshooting unrelated problem I am back to the ancient , never satisfactory answered , issues.

    My system starts with UEFI setup - not BIOS.
    I have an access to "boot menu" - via F11 .
    One of the items in such menu in named "ubuntu".
    My wild guess it is related to "grub".
    I am presently limping along with booting from USB drive - painfully slow process - but
    I get to "grub" options eventually , however, the USB drive is not there.
    In theory - only time I should end with ":grub" when I have a mutiboot system.
    For safety reasons I disabled my SATA controller , have no other USB EFI boot enabled drives and still getting this inaccessible OS option
    in "grub".

    Who creates "ubuntu" (label?) and why?
    How does "default UEFI " works , especialy with "grub" ?
    When I enable "USB" in my UEFI setup - why "default UEFI " option does not identify my USB drive ?
    (Yes, my 2nd partition in USB drive is /boot/efi and it boots , slow , but surely. )

    And last - the F11 access to boot menu is nice but how the heck I clear it - it keeps growing with non existent hardware...

    Thanks
    Cheers

  4. #4
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    Re: UEFI / grub / "ubuntu" small issues

    You asked similar question in another thread that really should have been here anyway.
    Moved that question & some info to this thread.

    Post this:

    sudo efibootmgr -v

    What brand/model system?
    For more info on UEFI boot install & repair - Regularly Updated :
    http://ubuntuforums.org/showthread.php?t=2147295
    Please use Thread Tools above first post to change to [Solved] when/if answered completely.

  5. #5
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    Re: UEFI / grub / "ubuntu" small issues

    To see boot order with UEFI:
    sudo efibootmgr -v

    That is basically what I get after pressing F11 - and it includes the "Ubuntu" - which is , as far as I can tell - access to grub.




    Sorry "oldfred" the original post was a reply in another thread and it got no response.
    I am not in habit to hijack so I posted my own.

    BTW I may be inclined to mark post solved when it is.
    Thanks for asking.

  6. #6
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    Re: UEFI / grub / "ubuntu" small issues

    The command efibootmgr with the -v shows lots of details. We need to see that.
    Grub install uses efibootmgr to create new "ubuntu" entry.

    See also the man page on efibootmgr for details.
    man efibootmgr
    For more info on UEFI boot install & repair - Regularly Updated :
    http://ubuntuforums.org/showthread.php?t=2147295
    Please use Thread Tools above first post to change to [Solved] when/if answered completely.

  7. #7
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    Re: UEFI / grub / "ubuntu" small issues

    For information.

    BIOS = Basic Input/Output System. It is information stored on an integrated circuit chip that informs the motherboard what kind of computer it is. It is a settings utility for the motherboard that can be modified to account for different hardware connected to the motherboard.

    The BIOS setting utility has been replaced with a Unified Extensible Firmware Interface (UEFI) settings utility.

    https://en.wikipedia.org/wiki/Unifie...ware_Interface

    I have some questions. Did you install Ubuntu on the hard drive? If so, that would be how the Ubuntu boot option was entered into the UEFI settings utility. Disabling the Sata controller will prevent UEFI from passing the boot process on to the Grub bootloader which has its core code and other data stored on the Sata hard drive. This is why you are getting the "Inaccessible OS" message.

    On the other hand, if Ubuntu is installed on a removable USB drive then the Ubuntu entry in the UEFI may not be pointing to the USB drive and that is the reason for the Inaccessible OS message.

    I do not have a UEFI motherboard. So I cannot explain how to edit the entries in UEFI. The motherboard manufacture should provide information on how to do that.

    Regards
    It is a machine. It is more stupid than we are. It will not stop us from doing stupid things.
    Ubuntu user #33,200. Linux user #530,530


  8. #8
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    Re: UEFI / grub / "ubuntu" small issues

    Good and bad news
    I am writing this while installing clean Ubuntu onto USB "stick"' drive - hopefully with UEFI boot partition. Painfully slow process.
    AFTER I can successfully boot using this USB drive I am going to repeat installation and attempt to install NEW OS onto drive I cannot currently boot from (missing UEFI boot partition) AND hopefully KEEP the existing partitions and data.

    I am believe that my problem started with UEFI setup - it was cluttered with so many boot options, but now it is pretty clean.


    However - I probably had an issue with mixing "legacy USB" with UEFI , I have USB3 drive too.
    Like to know what is "legacy USB" , my guess it boots via BIOS .


    Good point about disabling SATA , however since I had boot-able USB grub should have caught that.
    BUT - there should be ONLY ONE grub and I have no idea on which device it resided. Maybe in future I'll make sure to have groub on physically accessible USB .
    I keep my USB disks out of sight.


    Interesting note - after specifically disabling the UEFI "fast boot mode " after restart it is back to "fast boot mode "....
    PS It has been installing for over an hour ... time for coffee

  9. #9
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    Re: UEFI / grub / "ubuntu" small issues

    Full install to USB flash drive is slow.
    You probably will get grub installed to ESP on internal drive.
    Ubuntu's Ubiquity only installs grub boot files to first drives ESP - efi system partition. That normally is the Windows drive.
    While that will be bootable, it only boots with flash drive plugged in.

    Posted work around to manually unmount & mount correct ESP during install #23 & #26
    https://bugs.launchpad.net/ubuntu/+s...y/+bug/1396379
    Others suggest disconnecting all other drives physically or logically in UEFI settings, so install drive is first drive.
    Or removing boot flag/esp flag from first drive, so only ESP is install drive. (I have not had that work, but others have.)
    Or if you have ESP on second or external drive, you can just reinstall grub, either manually or using Boot-Repair's advanced mode & full reinstall to correct drive.
    For more info on UEFI boot install & repair - Regularly Updated :
    http://ubuntuforums.org/showthread.php?t=2147295
    Please use Thread Tools above first post to change to [Solved] when/if answered completely.

  10. #10
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    Re: UEFI / grub / "ubuntu" small issues

    It's going....
    Here is my real concern, but from years of experience this is pretty normal.
    Installing SINGLE OS is pretty starlight forward...
    Running a SIMPLE application is no breiner either.

    Building mutiboot system gets unnecessary complex - see few posts about dual boot Windows and Linux..

    Replacing BIOS with UEFI when each vendor implements it his way is a disaster..

    Mixing USB (versins) with SATA where boot priorities are "by guess by golly " lead to my problem.

    Adding more that one RADI5 array - mixing USB abd SATA is no fun

    BUT when "grub" ends in "limited edit mode " one is stuck
    When "grub advanced recovery mode" ends in "welcome to emergency recovery " - one ends up "try this , try that ..."

    Moral of (my) story when boot does not complete next best step is to do is
    the old "if MS designed cars... roll all windows down and restart " -- or get an new computer.

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