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Re: UEFI question

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crankypuss a écrit :
> 
> I have multiple linux root partitions on a single USB stick.  Some of 
> these partitions contain only one kernel, others contain several, but 
> they are all bootable linux installs, and they are all 32-bit builds.
> 
> Each such USB stick is used for backup/rescue/recovery.  I need to boot 
> any of these on 3 different machines which have different firmware:
> 
> Acer AOA150: 32-bit processor, legacy BIOS.
> 
> Dell XPS13: 64-bit processor, UEFI Firmware, but will boot in legacy 
> mode if the boot partition is physical (not logical) and its boot flag 
> is set.

"Physical" ? Do you mean "primary" ?

> ASUS T150: 64-bit processor with 32-bit UEFI Firmware, will not even 
> consider booting a non-UEFI device.
> 
> I've been successfully handling the Acer/Dell cases with MSDOS partition 
> table having one physical partition (boot flag set, grub2 installed) 
> followed by an extended partition containing the other distros, one per 
> partition.
> 
> I'm trying to understand how to add the ASUS case to the mix.  As far as 
> I can tell the ASUS pushes me to using a GPT partition table, but beyond 
> that the details get a little fuzzy.

If the UEFI firmware complies to the UEFI specification, it should
accept to boot from an MSDOS partition table. The drive must contain a
small EFI system partition of type 0xEF formated as FAT (I don't know if
it must be primary or can be logical) where you can install GRUB EFI or
another EFI compatible boot loader as the default loader
EFI/boot/bootx64.efi for a 64-bit firmware or EFI/boot/bootia32.efi for
a 32-bit firmware. Beware, there are 64-bit machines with 32-bit UEFI
firmware.

If the firmware cannot boot from an MSDOS partition table, you'll have
to convert the table to GPT with tools such as gdisk, and reinstall the
legacy and EFI bootloaders. GRUB PC (BIOS) likes to have a small "BIOS
boot" partition on a GPT disk, but it is not mandatory.

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UEFI question crankypuss <invalid@invalid.invalid> - 2015-12-30 05:11 -0700
  Re: UEFI question Pascal Hambourg <boite-a-spam@plouf.fr.eu.org> - 2015-12-30 13:35 +0100
    Re: UEFI question crankypuss <invalid@invalid.invalid> - 2015-12-30 06:03 -0700
      Re: UEFI question Bit Twister <BitTwister@mouse-potato.com> - 2015-12-30 13:48 +0000
        Re: UEFI question crankypuss <invalid@invalid.invalid> - 2015-12-30 14:10 -0700
          Re: UEFI question "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2015-12-30 16:26 -0500
            Re: UEFI question Pascal Hambourg <boite-a-spam@plouf.fr.eu.org> - 2015-12-31 10:21 +0100
              Re: UEFI question "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2015-12-31 08:50 -0500
                Re: UEFI question Pascal Hambourg <boite-a-spam@plouf.fr.eu.org> - 2015-12-31 16:19 +0100
                Re: UEFI question crankypuss <invalid@invalid.invalid> - 2015-12-31 11:51 -0700
                Re: UEFI question Bit Twister <BitTwister@mouse-potato.com> - 2015-12-31 19:34 +0000
                Re: UEFI question Pascal Hambourg <boite-a-spam@plouf.fr.eu.org> - 2015-12-31 21:52 +0100
                Re: UEFI question "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2016-01-01 18:58 -0500
                Re: UEFI question Pascal Hambourg <boite-a-spam@plouf.fr.eu.org> - 2016-01-02 02:19 +0100
                Re: UEFI question blind Pete <0123peter@gmail.com> - 2016-01-03 16:30 +1100
                Re: UEFI question Pascal Hambourg <boite-a-spam@plouf.fr.eu.org> - 2016-01-03 11:12 +0100
                Re: UEFI question Eef Hartman <E.J.M.Hartman@gmail.com> - 2016-01-03 12:44 +0000
                Re: UEFI question Pascal Hambourg <boite-a-spam@plouf.fr.eu.org> - 2016-01-03 15:16 +0100
                Re: UEFI question blind Pete <0123peter@gmail.com> - 2016-01-03 23:12 +1100
                Re: UEFI question Pascal Hambourg <boite-a-spam@plouf.fr.eu.org> - 2016-01-03 15:22 +0100
                Re: UEFI question crankypuss <invalid@invalid.invalid> - 2016-01-02 01:53 -0700
                Re: UEFI question Pascal Hambourg <boite-a-spam@plouf.fr.eu.org> - 2016-01-02 12:08 +0100
                Re: UEFI question crankypuss <invalid@invalid.invalid> - 2016-01-02 10:47 -0700
            Re: UEFI question crankypuss <invalid@invalid.invalid> - 2015-12-31 02:37 -0700
          Re: UEFI question Bit Twister <BitTwister@mouse-potato.com> - 2015-12-30 22:18 +0000
      Re: UEFI question Pascal Hambourg <boite-a-spam@plouf.fr.eu.org> - 2015-12-31 10:16 +0100
        Re: UEFI question crankypuss <invalid@invalid.invalid> - 2015-12-31 02:46 -0700
      Re: UEFI question blind Pete <0123peter@gmail.com> - 2016-01-01 21:20 +1100
        Re: UEFI question crankypuss <invalid@invalid.invalid> - 2016-01-01 05:08 -0700
          Re: UEFI question Pascal Hambourg <boite-a-spam@plouf.fr.eu.org> - 2016-01-01 21:51 +0100
            Re: UEFI question crankypuss <invalid@invalid.invalid> - 2016-01-01 15:17 -0700
              Re: UEFI question Bit Twister <BitTwister@mouse-potato.com> - 2016-01-01 23:06 +0000
                Re: UEFI question crankypuss <invalid@invalid.invalid> - 2016-01-02 02:16 -0700
                Re: UEFI question Bit Twister <BitTwister@mouse-potato.com> - 2016-01-02 10:04 +0000
                Re: UEFI question crankypuss <invalid@invalid.invalid> - 2016-01-02 03:39 -0700
                Re: UEFI question blind Pete <0123peter@gmail.com> - 2016-01-03 15:20 +1100
          Re: UEFI question blind Pete <0123peter@gmail.com> - 2016-01-03 15:14 +1100

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