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diff --git a/docs/gnulinux/grub_cbfs.md b/docs/gnulinux/grub_cbfs.md index d1c5428a..a6a8b18f 100644 --- a/docs/gnulinux/grub_cbfs.md +++ b/docs/gnulinux/grub_cbfs.md @@ -1,215 +1,443 @@ +#Modifying the GRUB Configuration in Libreboot Systems + +--- + +[**Edit this Page**](https://libreboot.org/git.html#editing-the-website-and-documentation-wiki-style) -- [Back to Previous Index](https://libreboot.org/docs/gnulinux/) + +* [How to Get the GRUB Configuration File](#get_grub) + * [Download the Libreboot Utility Archive](#download_libreboot_util) + * [Get the Necessary Utilities](#get_utilities) + * [Get ROM Image](#get_rom) + * [Download a Pre-Compiled Image from the Libreboot Website](#pre_compiled) + * [Create an Image from the Current ROM](#create_from_current_rom) + * [Copy grubtest.cfg from ROM Image](#extract_grubtest) +* [How to Modify the GRUB Configuration File](#modify_grub_howto) +* [Change the GRUB Configuration that the Operating System Uses](#change_grub) + * [Without Re-Flashing ROM](#without_reflash) + * [With Flashing ROM](#with_reflash) + * [Change grubtest.cfg in ROM](#insert_modified_grubtest) + * [Change MAC Address in ROM](#change_mac) + * [Flash Updated ROM Image](#flash_updated_rom) + * [Reboot the Computer](#reboot) + * [Final Steps](#final_steps) + +This guide will go through all the steps to modify a GRUB configuration file +in Libreboot; this is so that the user doesn't have to manually boot +their operating system each time, by typing in commands at the GRUB command line. + +For the purposes of this guide, you can either modify the GRUB configuration file +that resides in the computer's ROM, or else you could modify the version that +exists within the operating system itself; both options will be explained here. + --- -title: How to replace the default GRUB configuration file -x-toc-enable: true -... - -Libreboot on x86 uses the GRUB -[payload](http://www.coreboot.org/Payloads#GRUB_2) by default, which -means that the GRUB configuration file (where your GRUB menu comes from) -is stored directly alongside libreboot 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. - -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 exist directly inside CBFS instead of inside the -GRUB payload 'memdisk' (which is itself stored in CBFS). - -You can either modify the GRUB configuration stored in the flash chip, -or you can modify a GRUB configuration file on the main storage which -the libreboot GRUB payload will automatically search for. - -Here is an excellent writeup about CBFS (coreboot filesystem): -<http://lennartb.home.xs4all.nl/coreboot/col5.html>. - -*This guide is only for the GRUB payload. If you use the depthcharge payload, -ignore this section entirely.* - -Introduction ------------- - -Download the latest release from [libreboot.org](/)\ -*If you downloaded from git, refer to -[../git/\#build\_meta](../git/#build_meta) before continuing.* - -There are several advantages to modifying the GRUB configuration stored -in CBFS, but this also means that you have to flash a new libreboot ROM -image on your system (some users feel intimidated by this, to say the -least). Doing so can be risky if not handled correctly, because it can -result in a bricked system (recovery is easy if you have the -[equipment](../install/bbb_setup.md) for it, but most people don't). -If you aren't up to that then don't worry; it is possible to use a -custom GRUB menu without flashing a new image, by loading a GRUB -configuration from a partition on the main storage instead. - -1st option: don't re-flash ---------------------------- - -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 is on a dedicated -partition), and then use it automatically. - -Simply create your custom GRUB configuration and save it to -`/boot/grub/libreboot_grub.cfg` on the running system. The next time -you boot, GRUB (in libreboot) will automatically switch to this -configuration file. *This means that you do not have to re-flash, -recompile or otherwise modify libreboot at all!* - -Ideally, your distribution should automatically generate a -libreboot\_grub.cfg file that is written specifically under the -assumption that it will be read and used on a libreboot system that uses -GRUB as a payload. If your distribution does not do this, then you can -try to add that feature yourself or politely ask someone involved with -or otherwise knowledgeable about the distribution to do it for you. The -libreboot\_grub.cfg could either contain the full configuration, or it -could chainload another GRUB ELF executable (built to be used as a -coreboot payload) that is located in a partition on the main storage. - -If you want to adapt a copy of the existing *libreboot* GRUB -configuration and use that for the libreboot\_grub.cfg file, then follow -[\#tools](#tools), [\#rom](#rom) and -[\#extract\_testconfig](#extract_testconfig) to get the -`grubtest.cfg`. Rename `grubtest.cfg` to -`libreboot_grub.cfg` and save it to `/boot/grub/` on the -running system where it is intended to be used. Modify the file at that -location however you see fit, and then stop reading this guide (the rest -of this page is irrelevant to you); in `libreboot_grub.cfg` on disk, if -you are adapting it based on grub.cfg from CBFS then remove the check -for `libreboot_grub.cfg` otherwise it will loop. - -2nd option: re-flash --------------------- - -You can modify what is stored inside the flash chip quite easily. Read -on to find out how. - -Acquire the necessary utilities -------------------------------- - -Use `cbfstool` and `flashrom`. There are available in the -*libreboot\_util* release archive, or they can be compiled (see -[../git/\#build\_flashrom](../git/#build_flashrom)). Flashrom is also -available from the repositories: - - # pacman -S flashrom - -Acquiring the correct ROM image -------------------------------- + +##How to Get the GRUB Configuration File <a name=get_grub></a> + +The first step of the process is to actually get a hold of the GRUB configuration file +that we need to modify. There are two ways to do this: + +1. We can extract the one that already exists within the ROM +2. We can use one of the pre-compiled ROMS supplied by the Libreboot project + +However, both ways will require us to download the Libreboot Utility Archive. + +###Download the Libreboot Utility Archive <a name=download_libreboot_util></a> + +The Libreboot Utility Archive contains the programs that we'll need +to get our **grubtest.cfg** file. The latest release of the Libreboot Utility Archive +can be downloaded from libreboot.org, [here](https://www.mirrorservice.org/sites/libreboot.org/release/stable/20160907/libreboot_r20160907_util.tar.xz). +The quickest way to download it would be to use the **`wget`** program, +which (if you don't know) allows you to download files from the internet. + +If you don't already have it installed, you can install it, +using the **`apt-get`** command (in Debian-based distributions): + +> $ sudo apt-get install wget + +You can install it in Arch-based systems, using **`pacman`**: + +> $ sudo pacman -S wget + +Once you've installed **`wget`**, use it to download the file, +simply by passing it the URL as an argument; you can save the file anywhere, +but for the purpose of this guide, save it in **~/Downloads** +(your **Home** directory's downloads folder). +First, change the current working directory to **~/Downloads**: + +> $ cd ~/Downloads + +This guide assumes you are using the **20160907** version of Libreboot; +if using a different version, modify the following commands accordingly: + +> $ wget https://www.mirrorservice.org/sites/libreboot.org/release/stable/20160907/\ +> >libreboot_r20160907_util.tar.xz + +After the file is downloaded, use the **`tar`** command to extract its contents: + +> $ tar -xf libreboot_r20160907_util.tar.xz + +After extraction, the folder will have the same name as the archive: in this case, +**libreboot\_r20160907\_util**. For simplicity's sake, we'll rename it **libreboot\_util**, +using the **`mv`** command: + +> $ mv "libreboot_r20160907_util" "libreboot_util" + +Now you have the folder with all the utilities necessary to read and modify the contents of the ROM. + +###Get the Necessary Utilities <a name=get_utilities></a> + +Once you have the **libreboot\_util** archive, you can find the **`cbfstool`** and **`flashrom`** +utilities in **libreboot\_util/cbfstools/x86\_64/cbfstool**, +and **libreboot\_util/flashrom/x86\_64/flashrom**, respectively. + +>NOTE: This guide assumes that you are using a device with the **x86_64** architecture; +>if you are using a device with a different architecture (e.g., **i686** or **armv7l**), +>the proper version of **`cbfstool`** and **`flashrom`** will be in that folder, +>inside their respective directories. + +You could also compile both of these utilities; see [How to Build flashrom](../git/#build_flashrom). + +**`flashrom`** is also available from the repositories; if using an Arch-based distribution, +use **`pacman`**: + +> $ sudo pacman -S flashrom + +Or, if you have a Debian-based distribution, use **`apt-get`**: + +> $ sudo apt-get install flashrom + +###Get the ROM Image <a name=get_rom></a> 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 *libreboot.rom*, so please make sure to adapt. +flashed. For the purpose of this tutorial, it is assumed that your ROM +image file is named **libreboot.rom**, so please make sure to adapt. + +There are two ways to get a pre-compiled ROM image: +####1. Download a Pre-Compiled Image from the Libreboot Website <a name=pre_compiled></a> + +>For the current release, **20160907**, they can be found [here](https://www.mirrorservice.org/sites/libreboot.org/release/stable/20160907/rom/grub/); +>please adopt this guide, if using a different version of Libreboot. + +>You also need to make sure that you select both the correct ROM for the device you're using, +>as well as the correct flash chip size (if applicable): 4mb, 8mb, or 16mb; +>variable flash chip sizes only apply for the Thinkpads that Libreboot supports (excluding the X60 and T60). + +>You can find the flash chip size, by running the following command: + +>> # flashrom -p internal -V + +>Look for a line like this: + +>> Found Macronix flash chip "MX25L6406E/MX25L6408E" (8192 kB, SPI) \ +>> mapped at physical address 0x00000000ff800000. + +>Running this command on my Thinkpad X200 gives me the above result, so I know that +>my flash chip size is 8mb. + +>Once you've determined the correct ROMs and flash chip size, download them from the website. +>Since I'm currently using an X200 to write this guide, I'll demonstrate how +>to download the correct ROM images for that model. + +>First, we're going to navigate to the **libreboot\_util** folder: + +>> $ cd ~/Downloads/libreboot_util/ + +>Then, we will download the ROM images, using **`wget`**: + +>> $ wget https://www.mirrorservice.org/sites/libreboot.org/release/stable/\ +>> 20160907/rom/grub/libreboot_r20160907_grub_x200_8mb.tar.xz -ROM images are included pre-compiled in libreboot. You can also dump -your current firmware, using flashrom: +>Extract the archive, using **`tar`**: - $ sudo flashrom -p internal -r libreboot.rom - # flashrom -p internal -r libreboot.rom +>> $ tar -xf libreboot_r20160907_grub_x200_8mb.tar.xz -If you are told to specify the chip, add the option `-c {your chip}` to the -command, for example: +>Navigate to the directory that you just created: - # flashrom -c MX25L6405 -p internal -r libreboot.rom +>> $ cd libreboot_r20160907_grub_x200_8mb -Extract grubtest.cfg from the ROM image ---------------------------------------- +>Now that we are in the archive, we must choose the correct ROM image. +>To figure out the correct image, we must first parse the filenames for each ROM. +>For example, for the file named **x200_8mb_usqwerty_vesafb.rom**: -You can check the contents of the ROM image, inside CBFS: +>> Model Name: x200 +>> Flash Chip Size: 8mb +>> Country: us +>> Keyboard Layout: qwerty +>> ROM Type: vesafb or txtmode - $ cd .../libreboot\_util/cbfstool - $ ./cbfstool libreboot.rom +>Since I am using a QWERTY keyboard, I will ignore all the non-QWERTY options. +>Note that there are two types of ROMs: **`vesafb`** and **`txtmode`**; +>The **`vesafb`** ROM images are recommended, in most cases; **`txtmode`** ROM images +>come with **`MemTest86+`**, which requires text-mode, instead of the usual framebuffer +>used by coreboot native graphics initialization. -The files *grub.cfg* and *grubtest.cfg* should be present. grub.cfg is -loaded by default, with a menuentry for switching to grubtest.cfg. In -this tutorial, you will first modify and test *grubtest.cfg*. This is to -reduce the possibility of bricking your device, so DO NOT SKIP THIS! +>I'll choose **x200_8mb_usqwerty_vesafb.rom**; I'll copy the file (to the **`cbfstool`** directory), +>and rename it with one command: -Extract grubtest.cfg from the ROM image: +>> $ mv "x200_8mb_usqwerty_vesafb.rom" ../cbfstool/x86_64/cbfstool/x86_64/libreboot.rom - $ ./cbfstool libreboot.rom extract -n grubtest.cfg -f grubtest.cfg +####2. Create an Image from the Current ROM <a name=create_from_current_rom></a> -Modify the grubtest.cfg accordingly. +>The simpler way to get a ROM image is to just create it from your current ROM, +>using **`flashrom`**, making sure to save it in the **`cbfstool`** folder, inside **libreboot\_util**: -Re-insert the modified grubtest.cfg into the ROM image ------------------------------------------------------- +>> $ sudo flashrom -p internal -r ~/Downloads/libreboot_util/cbfstool/\ +>> x86_64/cbfstool/x86_64/libreboot.rom -Once your grubtest.cfg is modified and saved, delete the unmodified -config from the ROM image: +>If you are told to specify the chip, add the option **`-c {your chip}`** to the command, like this: + +>> $ sudo flashrom -c MX25L6405 -p internal -r ~/Downloads/libreboot_util/\ +>> cbfstool/x86_64/cbfstool/x86_64/libreboot.rom + +Now you are ready to extract the GRUB configuration files from the ROM, and modify them the way you want. + + +###Copy grubtest.cfg from the ROM Image <a name=extract_grubtest></a> + +You can check the contents of the ROM image, inside CBFS, using **`cbfstool`**. +First, navigate to the cbfstool folder: + +> $ cd ~/Downloads/libreboot_util/cbfstool/x86_64/cbfstool/x86_64/ + +Then, run the **`cbfstool`** commmand, with the **`print`** option; this will display +a list of all the files located in the ROM: + +> $ ./cbfstool libreboot.rom print + +You should see **grub.cfg** and **grubtest.cfg** in the list. **grub.cfg** is +loaded by default, with a menu entry for switching to **grubtest.cfg**. In +this tutorial, you will first modify and test **grubtest.cfg**. This is to +reduce the possibility of bricking your device, so *DO NOT SKIP THIS!* + +Extract (i.e., get a copy of ) **grubtest.cfg** from the ROM image: + +> $ ./cbfstool libreboot.rom extract -n grubtest.cfg -f grubtest.cfg + +By default **`cbfstool`** will extract files to the current working directory; +so, **grubtest.cfg** should appear in the same folder as **libreboot.rom**. + +--- - $ ./cbfstool libreboot.rom remove -n grubtest.cfg +##How to Modify the GRUB Configuration File <a name=modify_grub_howto></a> -Next, insert the modified version: +This section will instruct the user *how* to modify their GRUB configuration file; +whether they decide to use the version located in their operating system's **/** folder, +or the one located in the ROM, the modifications will be the same. - $ ./cbfstool libreboot.rom add -n grubtest.cfg -f grubtest.cfg -t raw +Once the file is open, look for the following line (it will be towards the bottom of the file): -Testing -------- +> menuentry 'Load Operating System [o]' --hotkey='o' --unrestricted -Now you have a modified ROM. Refer back to -[../install/\#flashrom](../install/#flashrom) for information on how to -flash it. +After this line, there will be an opening bracket **{**, followed by a several lines +of code, and then a closing bracket **}**; delete everything that is between those two brackets, +and replace it with the following code, if you're using an Arch-based disribution (e.g., Parabola GNU+Linux-Libre): - $ cd /libreboot\_util - # ./flash update libreboot.rom +> cryptomount -a +> set root='lvm/matrix-root' +> linux /boot/vmlinuz-linux-libre root=/dev/matrix/root cryptdevice=/dev/sda1:root \ +> cryptkey=rootfs:/etc/mykeyfile +> initrd /boot/initramfs-linux-libre.img -Ocassionally, coreboot changes the name of a given board. If flashrom +Or, replace it with this, if you are using a Debian-based distribution (e.g., Trisquel GNU+Linux): + +> cryptomount -a +> set root='lvm/matrix-rootvol' +> linux /vmlinuz root=/dev/mapper/matrix-rootvolcryptdevice=/dev/mapper/matrix-rootvol:root +> initrd /initrd.img + +Remember, that these names come from the instructions to install GNU+Linux +on Libreboot systems, located [here](index.md). If you followed different instructions, +(or for some other reason, used different names), simply put the names +of your **root** and **swap** volumes, in place of the ones used here. + +This covers the basic changes that we can make to GRUB; however, there are some more +changes that you could make, to increase the security of your GRUB configuration. +If you are interested in those modifications, see the Libreboot guide on [Hardening GRUB](grub_hardening.md). + +That's it for the modifications! Now all you need to do is follow the instructions below, +in order to use this new configuration to boot your system. + +--- + +##Change the GRUB Configuration File that the Operating System Uses <a name=change_grub></a> + +Now that we have explained *how* to modify the file itself, we need to explain +how to actually make our system *use* the new GRUB configuration file to boot. + +###Without Re-Flashing the ROM <a name=without_reflash></a> + +To change the GRUB Configuration that our system uses, without having to re-flash the ROM, +we need to take our **grubest.cfg** file, rename it to **libreboot\_grub**; +this is because that, 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** is on a dedicated partition), and then use it automatically. + +Therefore, we need to either copy **libreboot\_grub.cfg** to **/grub**, or to **/boot/grub**: + +> $ sudo cp ~/Downloads/libreboot_util/cbfstool/x86_64/cbfstool/x86_64/grubtest.cfg \ +> >/boot/grub # or /grub + +Now, the next time we boot our computer, GRUB (in Libreboot) will automatically switch +to this configuration file. *This means that you do not have to re-flash, +recompile, or otherwise modify Libreboot at all!* + +###With Re-Flashing the ROM <a name=with_reflash></a> + +Changing the GRUB configuration that resides in ROM is a bit more complicated +that the one in **/**, but most of the hard work is already done. + +####Change grubtest.cfg in ROM <a name=insert_modified_grubtest></a> + +Now that you have the modified **grubtest.cfg**, we need to remove +the old **grubtest.cfg** from the ROM, and put in our new one. To remove +the old one, we will use **`cbfstool`**: + +> $ ./cbfstool libreboot.rom remove -n grubtest.cfg + +Then, add the new one to the ROM: + +> $ ./cbfstool libreboot.rom add -n grubtest.cfg -f grubtest.cfg -t raw + +####Change MAC address in ROM <a name=change_macl></a> + +The last step before flashing the new ROM, is to change the MAC address inside it. +Every libreboot ROM image contains a generic MAC address; you want to make sure +that your ROM image contains yours, so as to not create any problems on your network +(say, for example, that multiple family members had libreboot computers, and used +the same ROM image to flash those computers). + +To do this, we will use the **`ich9gen`** utility, also located in **libreboot_util**. + +First, you need to find the current MAC address of your computer; there are +two ways to do this: + +1. Read the white label on the bottom of the case (however, this will only work, +if your motherboard has never been replaced). +2. Run **`ifconfig`**; look for your ethernet device (e.g., **`enpXXX`** +in Arch-based distributions, or **`eth0`** in Debian-based distributions), +and look for a set of characters like this: **`00:f3:f0:45:91:fe`**. + +Next, you need to move **libreboot.rom** to the following folder; this is where +the executable for **`ich9gen`** is located: + +> $ mv libreboot.rom ~/Downloads/libreboot_r20160907_util/ich9deblob/ + +Once there, run the following command, making sure to use your own MAC address, +instead of what's written below: + +> $ ./ich9gen --macaddress XX:XX:XX:XX:XX:XX + +Three new files will be created: + +* ich9fdgbe_4m.bin: this is for GM45 laptops with the 4MB flash chip. +* ich9fdgbe_8m.bin: this is for GM45 laptops with the 8MB flash chip. +* ich9fdgbe_16m.bin: this is for GM45 laptops with the 16MB flash chip. + +Look for the one that corresponds to the size of your ROM image; for example, +if your flash chip size is **`8mb`**, you'll want to use **ich9fdgbe_8m.bin**. + +Now, insert this file (called the **`descriptor+gbe`**) into the ROM image, using **`dd`**: + +> dd if=ich9fdgbe_8m.bin of=libreboot.rom bs=1 count=12k conv=notrunc + +Move **libreboot.rom** back to the **libreboot\_util** directory: + +> $ mv libreboot.rom ~/Downloads/libreboot_util + +You are finally ready to flash the ROM! + +####Flash Updated ROM Image <a name=flash_updated_rom></a> + +The last step of flashing the ROM requires us to change our current working directory +to **libreboot\_util**: + +> $ cd ~/Downloads/libreboot_util + +Now, all we have to do is use the **`flash`** script in this directory, +with the **`update`** option, using **libreboot.rom** as the argument: + +> $ sudo ./flash update libreboot.rom + +Ocassionally, coreboot changes the name of a given board. If **`flashrom`** complains about a board mismatch, but you are sure that you chose the correct ROM image, then run this alternative command: - # ./flash forceupdate libreboot.rom +> $ sudo ./flash forceupdate libreboot.rom + +You will see the **`flashrom`** program running for a little while, and you might see errors, +but if it says **`Verifying flash... VERIFIED`** at the end, then it’s flashed, +and should boot. If you see errors, try again (and again, and again). +The message **`Chip content is identical to the requested image`** is also +an indication of a successful installation. -You should see `Verifying flash... VERIFIED.` written at the end -of the flashrom output. Once you have done that, shut down and then boot -up with your new test configuration. +####Reboot the Computer <a name=reboot></a> -Choose (in GRUB) the menu entry that switches to grubtest.cfg. If it -works, then your config is safe and you can continue below. +Now that you have flashed the image, reboot the computer. Keep pressing **`spacebar`** +right after you turn it on, until you see the GRUB menu, to prevent libreboot +from automatically trying to load the operating system. -*If it does not work like you want it to, if you are unsure or -sceptical in any way, then re-do the steps above until you get it right! -Do not proceed past this point unless you are 100% sure that your -new configuration is safe (or desirable) to use.* +Scroll down with the arrow keys, and choose the **`Load test configuration (grubtest.cfg) inside of CBFS`** option; +this will switch the GRUB configuration to your test version. If all goes well, +it should prompt you for a GRUB username and password, and then your LUKS password. -Final steps ------------ +Once the operating system starts loading, it will prompt you for your LUKS password again. +If it continues, and loads into the OS without errors, then that means your flashing +attempt was a success. -When you are satisfied booting from grubtest.cfg, you can create a copy -of grubtest.cfg, called grub.cfg. This is the same except for one -difference: the menuentry 'Switch to grub.cfg' will be changed to -'Switch to grubtest.cfg' and inside it, all instances of grub.cfg to -grubtest.cfg. This is so that the main config still links (in the menu) -to grubtest.cfg, so that you don't have to manually switch to it, in -case you ever want to follow this guide again in the future (modifying -the already modified config). From /libreboot\_util/cbfstool, do: +####Final Steps <a name=final_steps></a> - # sed -e 's:(cbfsdisk)/grub.cfg:(cbfsdisk)/grubtest.cfg:g' -e +When you are satisfied booting from **grubtest.cfg**, you can create a copy +of **grubtest.cfg**, called **grub.cfg**. -'s:Switch to grub.cfg:Switch to grubtest.cfg:g' < grubtest.cfg > -grub.cfg +First, go to the **`cbfstool`** directory: -Delete the grub.cfg that remained inside the ROM: +> $ cd ~/Downloads/libreboot_util/cbfstool/x86_64/cbfstool/x86_64/ - $ ./cbfstool libreboot.rom remove -n grub.cfg +Then, create a copy of **grubest.cfg**, named **grub.cfg**: -Add the modified version that you just made: +> $ cp grubtest.cfg ./grub.cfg - $ ./cbfstool libreboot.rom add -n grub.cfg -f grub.cfg -t raw +Now you will use the **`sed`** command to make several changes to the file: +the menu entry **`'Switch to grub.cfg'`** will be changed to **`Switch to grubtest.cfg`**, +and inside it, all instances of **grub.cfg** to **grubtest.cfg**. +This is so that the main config still links (in the menu) to **grubtest.cfg**, +so that you don't have to manually switch to it, in case you ever want to follow +this guide again in the future (modifying the already modified config).: -*Now you have a modified ROM. Again, refer back to -[../install/\#flashrom](../install/#flashrom) for information on how to -flash it. It's the same method as you used before. Shut down and then -boot up with your new configuration.* +> $ sed -e 's:(cbfsdisk)/grub.cfg:(cbfsdisk)/grubtest.cfg:g' -e \ +> >'s:Switch to grub.cfg:Switch to grubtest.cfg:g' < grubtest.cfg > \ +> >grub.cfg -Copyright © 2014, 2015 Leah Rowe <info@minifree.org>\ -Copyright © 2015 Jeroen Quint <jezza@diplomail.ch>\ +Move **libreboot.rom** from **libreboot\_util** to your current directory: + +> $ mv ~/Downloads/libreboot_util/libreboot.rom . + +Delete the **grub.cfg** that's already inside the ROM: + +> $ ./cbfstool libreboot.rom remove -n grub.cfg + +Add your modified **grub.cfg** to the ROM: + +> $ ./cbfstool libreboot.rom add -n grub.cfg -f grub.cfg -t raw + +Move **libreboot.rom** back to **libreboot\_util**: + +> $ mv libreboot.rom ../.. + +If you don't remember how to flash it, refer back to [Flash Updated ROM Image](#flash_updated_rom); +it's the same method as you used before. Afterwards, reboot the machine with your new configuration. + +--- + +Copyright © 2014, 2015, 2016 Leah Rowe <info@minifree.org> + +Copyright © 2017 Elijah Smith <esmith61412@posteo.net> + +--- 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 this license is found in [../fdl-1.3.md](../fdl-1.3.md) +A copy of this license is found in [../fdl-1.3.md](../fdl-1.3.md)
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