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On Monday, 23 September 2019 08:43:52 BST Adam Carter wrote: |
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> On Mon, Sep 23, 2019 at 3:38 PM J. Roeleveld <joost@××××××××.org> wrote: |
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> > On 23 September 2019 07:33:44 CEST, Adam Carter <adamcarter3@×××××.com> |
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> > |
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> > wrote: |
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> > >Follow on question; what does efibootmgr actually modify? Is it writing |
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> > >to |
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> > >motherboard EEPROM values similar what happens when you write changes |
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> > >in |
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> > >the BIOS setup pages? |
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> > >If you, does mean I may have been able to fix this issue in the BIOS? |
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> > |
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> > It updates something in the CMOS, however, not all UEFI bioses support |
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> > manually editing this. |
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> > I haven't found a decent option for this on any system I own yet, apart |
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> > from efibootmgr. |
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> |
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> Ok thanks. |
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> |
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> Looks like the setting gets cleared with every BIOS update. I assume this |
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> is due to shitty coding by the MB manufacturer and not a limitation of UEFI. |
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|
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An update of the firmware flashes the UEFI EEPROM and as far as I have |
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experienced no settings are retained. A fresh probe of MoBo devices at first |
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boot re-lists anything bootable. |
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|
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Desktop/workstation UEFI firmware have more features, which allow tweaking |
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boot lists. Some also offer a back up/restore facility for settings from a |
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file. |
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|
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Laptop UEFI boot menus are more sparce, in which case efibootmgr, or with |
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systemd-boot the bootctl command allow managing UEFI boot entries. I believe |
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MSWindows have their own applications to do the same. |
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|
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Regarding the message "GUID partition table header signature is wrong", this |
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is probably indicative of an MBR partition table - but I'm not sure. Have you |
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installed some OS on an MBR partition schema? |
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|
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-- |
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Regards, |
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Mick |