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On Mon, 17 Aug 2015, Rod wrote: |
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> Hi list, |
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|
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Hi |
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> I'm trying to figure out how to make my boot partition to boot from UEFI, |
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> I have grub2 installed, but I keep getting a error when I ask it to install |
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> the boot information. |
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First things first, are you installing gentoo from an UEFI booted |
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installation media? From what I know the gentoo minimal install cd does |
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not allow for this, and I will assume you are using that. |
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|
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If you're using some other installation method, check whether the |
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directory /sys/firmware/efi/efivars has any content, try to mount efivarfs |
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following the instructions in this link: |
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https://wiki.gentoo.org/wiki/Efibootmgr#Configuration |
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and then check again. |
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|
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> # efibootmgr |
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> efibootmgr: EFI variables are not supported on this system. |
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> |
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> |
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> # grub2-install --target=x86_64-efi /dev/sdc |
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> Installing for x86_64-efi platform. |
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> efibootmgr: EFI variables are not supported on this system. |
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> efibootmgr: EFI variables are not supported on this system. |
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> Installation finished. No error reported. |
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In your case it seems that the system is not in an UEFI-booted state. But |
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we can work around this by using a nice part of the UEFI specification, |
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details below. |
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|
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> mount |
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> /dev/sdc1 201633 156 201478 1% /boot/efi |
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> |
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> I have the /boot/efi part mounted ok.. |
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Before we go further make sure that the partition is a valid EFI boot |
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partition: code EF00 (gdisk), partition flags boot/esp (for parted). |
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> How can I get this UEFI be become bootable without media to make it boot |
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> in to that mode to begin with ? |
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It's actually much easier than it may seem, and it's outlined here: |
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https://wiki.gentoo.org/wiki/GRUB2#Alternative:_using_the_default_UEFI_firmware_location |
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Basically, for all sorts of removable media there must be a way to tell |
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UEFI what to boot without having to hardcode the entries into NVRAM (like |
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efibootmgr does). Therefore UEFI firmware is supposed to check for the |
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first ESP partition on a drive and boot \EFI\boot\bootx64.efi from it. |
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This also works for harddrives, and since you can access a FAT partition |
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even when booted in bios mode you just put grub there. |
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Now this works perfectly well for a linux kernel with efi stub and cmdline |
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built-in, but grub may have trouble finding it's configuration files, I do |
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not know. So I suggest you try it. Find grubx64.efi in /boot/efi and copy |
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it to /boot/efi/EFI/BOOT/BOOTX64.EFI. Voila, should boot just fine. |
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On my first UEFI install I did not know about this, efibootmgr did not |
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work, but the handbook says to place the kernel at /EFI/boot/bootx64.efi |
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and it just magically worked. |
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Generally you will find that provided the UEFI implementation of your |
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vendor is not complete shit (lots of them exist) UEFI makes it generally |
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easier to handle booting. One partition and the EFI variables and you can |
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boot anything, no more hidden sectors. |
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