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Diffstat (limited to 'docs/gnulinux/grub_cbfs.html')
| -rw-r--r-- | docs/gnulinux/grub_cbfs.html | 181 |
1 files changed, 128 insertions, 53 deletions
diff --git a/docs/gnulinux/grub_cbfs.html b/docs/gnulinux/grub_cbfs.html index fe961ea..a037690 100644 --- a/docs/gnulinux/grub_cbfs.html +++ b/docs/gnulinux/grub_cbfs.html @@ -18,7 +18,7 @@ Libreboot uses the GRUB <a href="http://www.coreboot.org/Payloads#GRUB_2">payload</a> by default, which means that the GRUB configuration file (where your GRUB menu comes from) is stored directly alongside libreboot - and it's GRUB payload executable, inside + and its GRUB payload executable, inside the flash chip. In context, this means that installing distributions and managing them is handled slightly differently compared to traditional BIOS systems. </p> @@ -26,7 +26,7 @@ A libreboot (or coreboot) ROM image is not simply "flat"; there is an actual filesystem inside called CBFS (coreboot filesystem). A utility called 'cbfstool' allows you to change the contents of the ROM image. In this case, libreboot is configured - such that the 'grub.cfg' and 'grubtest.cfg' files exists directly inside CBFS instead of + such that the 'grub.cfg' and 'grubtest.cfg' files exist directly inside CBFS instead of inside the GRUB payload 'memdisk' (which is itself stored in CBFS). </p> <p> @@ -49,21 +49,32 @@ <ul> <li><a href="#getting_started">Getting started</a></li> - <li><a href="#libreboot_grub_config_ondisk">Don't want to flash a new ROM image?</a></li> - <li><a href="#build_cbfstool">Build 'cbfstool' from source</a></li> - <li><a href="#which_rom">Which ROM image should I use?</a></li> - <li><a href="#extract_grubtest">Extract grubtest from the ROM image</a> - <li> - <a href="#example_modifications">Example modifications for <i>grubtest.cfg</i></a> + <li><a href="#libreboot_grub_config_ondisk">Option A: don't flash a new ROM</a></li> + <li><a href="#libreboot_grub_config_flash">Option B: flash a new ROM</a></li> + <ul> + <li><a href="#tools">Get the tools ready</a></li> <ul> - <li><a href="#example_modifications_trisquel">Trisquel GNU/Linux-libre</a></li> - <li><a href="#example_modifications_parabola">Parabola GNU/Linux-libre</a></li> + <li><a href="#locate_tools">Locate the tools in the binary release</a></li> + <li><a href="#build_tools">Build the tools from source</a></li> </ul> - </li> - <li><a href="#reinsert_modified_grubtest">Re-insert the modified grubtest.cfg into the ROM image</a></li> - <li><a href="#test_it">Test it!</a> - <li><a href="#final_steps">Final steps</a></li> - <li><a href="#troubleshooting">Troubleshooting</a></li> + <li><a href="#which_rom">Which ROM image should I use?</a></li> + <ul> + <li><a href="#use_prebuilt_rom">Use one of the provided ROM images</a></li> + <li><a href="#re-use_rom">Re-use the currently flashed ROM image</a></li> + </ul> + <li><a href="#extract_grubtest">Extract grubtest from the ROM image</a> + <li> + <a href="#example_modifications">Example modifications for <i>grubtest.cfg</i></a> + <ul> + <li><a href="#example_modifications_trisquel">Trisquel GNU/Linux-libre</a></li> + <li><a href="#example_modifications_parabola">Parabola GNU/Linux-libre</a></li> + </ul> + </li> + <li><a href="#reinsert_modified_grubtest">Re-insert the modified grubtest.cfg into the ROM image</a></li> + <li><a href="#test_it">Test it!</a> + <li><a href="#final_steps">Final steps</a></li> + <li><a href="#troubleshooting">Troubleshooting</a></li> + </ul> </ul> </div> @@ -82,12 +93,6 @@ <p> <a href="#pagetop">Back to top of page.</a> </p> - - </div> - - <div class="section"> - - <h2 id="libreboot_grub_config_ondisk">Don't want to flash a new ROM image?</h2> <p> There are several advantages to modifying the GRUB configuration stored in CBFS, but @@ -100,6 +105,13 @@ from a partition on the main storage instead. </p> + + </div> + + <div class="section"> + + <h2 id="libreboot_grub_config_ondisk">Option A: don't flash a new ROM</h2> + <p> By default, GRUB in libreboot is configured to scan all partitions on the main storage for /boot/grub/libreboot_grub.cfg or /grub/libreboot_grub.cfg(for systems where /boot @@ -139,17 +151,58 @@ </div> <div class="section"> + + <h2 id="libreboot_grub_config_flash">Option B: flash a new ROM</h2> + + <p> + Alternatively to editing the GRUB configuration file on your disk, you can also change the configuration that is + stored in the CBFS on the flash chip. + </p> + + <p> + <a href="#pagetop">Back to top of page.</a> + </p> + + </div> + <div class="section"> + <h2 id="tools">Get the tools ready</h2> - <h2 id="build_cbfstool">Build 'cbfstool' from source</h2> + <p> + You will need to use the <b><i>cbfstool</i></b>, <b><i>rmodtool</i></b> and <b><i>flashrom</i></b> tools. + You can either use the pre-compiled binaries provided by the binary release of libreboot, or build the tools + yourself from source from the libreboot source code. + </p> + + <div class="subsection"> + <h3 id="locate_tools">Locate the tools in the binary release</h3> <p> - If you are working with libreboot_src, then you can run <b><i>make</i></b> command in - libreboot_src/coreboot/util/cbfstool to build the <b><i>cbfstool</i></b> and <b><i>rmodtool</i></b> - executable. + If you are working with the binary release libreboot_util, you will find the <b><i>cbfstool</i></b> and + <b><i>rmodtool</i></b> binaries under ./cbfstool/{architecture}/ , where {architecture} refers to your + hardware name for which your current running kernel is compiled for. You can find it by running: + <br/> + <b>$ uname -m</b> + </p> + <p> + The <b><i>flashrom</i></b> binary is located under ./flashrom/{architecture}/ </p> <p> - Alternatively if you are working with libreboot_util, you will find binaries under ./cbfstool/ + Whenever one of the tools is used in a command in this tutorial, it will be called as, e.g., ./cbfstool <br/> + Please adapt the paths accordingly (e.g.: cbfstool/i686/cbfstool). </p> + </div class="subsection"> + + <div class="subsection"> + <h3 id="build_tools">Build the tools from source</h3> + + <p> + If you are working with libreboot_src, then you can run <b><i>make</i></b> command in + libreboot_src/coreboot/util/cbfstool to build the <b><i>cbfstool</i></b> and <b><i>rmodtool</i></b> + executables. See <a href="../git/index.html#build_flashrom">../git/index.html#build_flashrom</a> for + instructions on how to build <b><i>flashrom</i></b>. + + </p> + </div class="subsection"> <p> <a href="#pagetop">Back to top of page.</a> @@ -162,21 +215,36 @@ <h2 id="which_rom">Which ROM image should I use?</h2> <p> - You can work directly with one of the ROM images already included in the libreboot ROM archives. For the purpose of - this tutorial it is assumed that your ROM image file is named <i>libreboot.rom</i>, so please make sure to adapt. + You can either work directly with one of the ROM images already included in the libreboot ROM archives, or re-use the ROM that + you have currently flashed. For the purpose of this tutorial it is assumed that your ROM image file is named <i>libreboot.rom</i>, + so please make sure to adapt. </p> - <p> - If you want to re-use the ROM that you currently have flashed (and running) then see - <a href="../git/index.html#build_flashrom">../git/index.html#build_flashrom</a> - and then run:<br/> - <b>$ sudo ./flashrom -p internal -r libreboot.rom</b><br/> - Notice that this is using <b>"-r"</b> (read) instead of <b>"-w"</b> (write). - This will create a dump (copy) of your current firmware and name it <b>libreboot.rom</b>. - You need to take ownership of the file. For example:<br/> - <b>$ sudo chown yourusername:yourusername libreboot.rom</b><br/> - <b># chown yourusername:yourusername libreboot.rom</b> - </p> + <div class="subsection"> + <h3 id="use_prebuilt_rom">Use one of the provided ROM images</h3> + <p> + All ROMs are located under ./bin/{computer_model}/ . Make a working copy of the ROM you want to use: + <br/> + <b>$ cp ./bin/{computer_model}/{computer_model}_{keyboard_layout}_{mode}.rom libreboot.rom</b> + <br/> + {keyboard_layout} defines the keyboard layout that will be available on the GRUB console. This might be important + if you protect GRUB with a password later on and want to insert non-ASCII characters. + {mode} can be <i>vesafb</i> or <i>txtmode</i> and starts GRUB with a background image or in text mode. + </p> + </div> + + <div class="subsection"> + <h3 id="re-use_rom">Re-use the currently flashed ROM image</h3> + <p> + If you want to re-use the ROM that you currently have flashed (and running) and then run:<br/> + <b>$ sudo ./flashrom -p internal -r libreboot.rom</b><br/> + Notice that this is using <b>"-r"</b> (read) instead of <b>"-w"</b> (write). + This will create a dump (copy) of your current firmware and name it <b>libreboot.rom</b>. + You need to take ownership of the file. For example:<br/> + <b>$ sudo chown yourusername:yourusername libreboot.rom</b><br/> + <b># chown yourusername:yourusername libreboot.rom</b> + </p> + </div> <p> If you currently have flashed a ROM image from an older version, it is recommended to update first: @@ -200,8 +268,8 @@ <p> The libreboot.rom file contains your <i>grub.cfg</i> and <i>grubtest.cfg</i> files. - You should extract, modify and re-insert the copy first. grub.cfg will load first, - but it has a menu entry for switching to the copy (grubtest.cfg). + grub.cfg will load first, but it has a menu entry for switching to the copy (grubtest.cfg). + Thus, you should extract, modify and re-insert the grubtest.cfg first. This reduces your chance of making a mistake that could make your machine unbootable (or very hard to boot). </p> @@ -211,7 +279,12 @@ </p> <p> - Now you have a grubtest.cfg in cbfstool directory. Edit it however you wish. + Make a copy of the original file, before you modify it:<br/> + <b>$ cp grubtest.cfg grubtest_vanilla.cfg</b> + </p> + + <p> + Now you have a grubtest.cfg in the cbfstool directory. Edit it however you wish. </p> <p> @@ -221,15 +294,14 @@ </div> <div class="section"> + <h2 id="example_modifications">Example modifications for <i>grubtest.cfg</i></h2> - <div class="subsection"> - - <h2 id="example_modifications">Example modifications for <i>grubtest.cfg</i></h2> + <p> + These are some common examples of ways in which the grubtest.cfg file can be modified. + </p> - <p> - These are some common examples of ways in which the grubtest.cfg file can be modified. - </p> + <div class="subsection"> <h3 id="example_modifications_trisquel">Trisquel GNU/Linux-libre</h3> <p> @@ -310,13 +382,15 @@ There are lots of possible variations so please try to adapt. </p> - <h3 id="example_modifications_parabola">Parabola GNU/Linux-libre</h3> + </div> - <p> - 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. - </p> + <div class="subsection"> + <h3 id="example_modifications_parabola">Parabola GNU/Linux-libre</h3> + <p> + 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. + </p> </div> <p> @@ -458,6 +532,7 @@ <p> Copyright © 2014, 2015 Francis Rowe <info@gluglug.org.uk><br/> + Copyright © 2015 Julian Mehne <juli@nmehne.de><br/> This document is released under the Creative Commons Attribution-ShareAlike 4.0 International Public License and all future versions. A copy of the license can be found at <a href="../license.txt">../license.txt</a>. </p> |