Date: Mon, 22 Aug 2016 10:22:04 +0100 Subject: actually add the documentation directory. (I forgot git add in last commit) --- docs/gnulinux/grub_config.html | 223 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 223 insertions(+) create mode 100644 docs/gnulinux/grub_config.html (limited to 'docs/gnulinux/grub_config.html') diff --git a/docs/gnulinux/grub_config.html b/docs/gnulinux/grub_config.html new file mode 100644 index 00000000..bde9541f --- /dev/null +++ b/docs/gnulinux/grub_config.html @@ -0,0 +1,223 @@ + + + + + + + + + Writing a GRUB configuration file + + + +

Writing a GRUB configuration file

+ This section is for those systems which use the GRUB payload. + If your system uses the depthcharge payload, ignore this section. +

+ Back to index +

+ +

+ Example modifications for grubtest.cfg +
- Trisquel GNU/Linux-libre
- Parabola GNU/Linux-libre
+

+ +

Example modifications for grubtest.cfg

+ +

+ These are some common examples of ways in which the grubtest.cfg file can be modified. +

+ +

Obvious option: don't even modify the built-in grub.cfg

+ Use the menuentry that says something like Search for GRUB outside CBFS. Assuming that you + have a grub.cfg file at /boot/grub/ in your installed distro, this will generate a new menuentry in + the GRUB menu. Use that to boot. +

+ Then do this as root:
+ $ cd /boot/grub/
+ $ ln -s grub.cfg libreboot_grub.cfg +

+ After that, your system should then boot automatically. +

+ +

Trisquel with full disk encryption, custom partition layout

+ GRUB can boot from a symlink (or symlinks) pointing to your kernel/initramfs, whether from an unencrypted or encrypted /boot/. You + can create your own custom symlink(s) but you have to manually update them when updating your kernel. This guide (not maintained by + the libreboot project) shows how to configure Trisquel to automatically update that symlink on every kernel update. + http://www.rel4tion.org/people/fr33domlover/libreboot-fix/ +

+ TODO: adapt those notes and put them here. The author said that it was CC-0, so re-licensing under GFDL shouldn't be a problem. +

+ +

Trisquel GNU/Linux-libre

+ +

+ As an example, on my test system in /boot/grub/grub.cfg (on the HDD/SSD) I see for the main menu entry: +

linux /boot/vmlinuz-3.15.1-gnu.nonpae root=UUID=3a008e14-4871-497b-95e5-fb180f277951 ro crashkernel=384M-2G:64M,2G-:128M quiet splash $vt_handoff
initrd /boot/initrd.img-3.15.1-gnu.nonpae

+ +

+ ro, quiet, splash, crashkernel=384M-2G:64M,2G-:128M and + $vt_handoff can be safely ignored. +

+ +

+ I use this to get my partition layout:
+ $ lsblk +

+ +

+ In my case, I have no /boot partition, instead /boot is on the same partition as / on sda1. + Yours might be different. In GRUB terms, sda means ahci0. 1 means msdos1, or gpt1, depending + on whether I am using MBR or GPT partitioning. Thus, /dev/sda1 is GRUB is (ahci0,msdos1) or + (ahci0,gpt1). In my case, I use MBR partitioning so it's (ahci0,msdos1). + 'msdos' is a GRUB name simply because this partitioning type is traditionally used by MS-DOS. + It doesn't mean that you have a proprietary OS. +

+ +

+ Trisquel doesn't keep the filenames of kernels consistent, instead it keeps old kernels and + new kernel updates are provided with the version in the filename. This can make GRUB payload + a bit tricky. Fortunately, there are symlinks /vmlinuz and /initrd.img + so if your /boot and / are on the same partition, you can set GRUB to boot from that. + These are also updated automatically when installing kernel updates from your distributions + apt-get repositories. + + Note: when using jxself kernel releases, + these are not updated at all and you have to update them manually. + +

+ +

+ For the GRUB payload grubtest.cfg (in the 'Load Operating System' menu entry), we therefore have (in this example):
+ set root='ahci0,msdos1'
+ linux /vmlinuz root=UUID=3a008e14-4871-497b-95e5-fb180f277951
+ initrd /initrd.img +

+ +

+ Optionally, you can convert the UUID to its real device name, for example /dev/sda1 in this case. + sdX naming isn't very reliable, though, which is why UUID is used for most distributions. +

+ +

+ Alternatively, if your /boot is on a separate partition then you cannot rely on the /vmlinuz and /initrd.img symlinks. + Instead, go into /boot and create your own symlinks (update them manually when you install a new kernel update).
+ $ sudo -s (or su -)
+ # cd /boot/
+ # rm -f vmlinuz initrd.img
+ # ln -s yourkernel ksym
+ # ln -s yourinitrd isym
+ # exit +

+ +

+ Then your grubtest.cfg menu entry (for payload) becomes like that, for example if / was on sda2 and /boot was on sda1:
+ set root='ahci0,msdos1'
+ linux /ksym root=/dev/sda2
+ initrd /isym +

+ +

+ There are lots of possible variations so please try to adapt. +

+ +

Parabola GNU/Linux-libre

+ +

+ You can basically adapt the above. Note however that Parabola does not keep old kernels still installed, and the file names + are always consistent, so you don't need to boot from symlinks, you can just use the real thing directly. +

+ +

+ Back to top of page. +

+ +

+ Copyright © 2014, 2015 Leah Rowe <info@minifree.org>
+ Permission is granted to copy, distribute and/or modify this document + under the terms of the GNU Free Documentation License, Version 1.3 + or any later version published by the Free Software Foundation; + with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. + A copy of the license can be found at ../gfdl-1.3.txt +

+ +

+ Updated versions of the license (when available) can be found at + https://www.gnu.org/licenses/licenses.html +

+ +

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