The operating system uses GNU GRUB as its boot loader
(see overview of GRUB in GNU GRUB Manual). It is
configured using a
grub-configuration declaration. This data type
is exported by the
(gnu system grub) module and described below.
The type of a GRUB configuration declaration.
This is a string denoting the boot device. It must be a device name
understood by the
grub-install command, such as
(hd0) (see Invoking grub-install in GNU GRUB Manual).
A possibly empty list of
menu-entry objects (see below), denoting
entries to appear in the GRUB boot menu, in addition to the current
system entry and the entry pointing to previous system generations.
The index of the default boot menu entry. Index 0 is for the entry of the current system.
The number of seconds to wait for keyboard input before booting. Set to 0 to boot immediately, and to -1 to wait indefinitely.
grub-theme object describing the theme to use.
The GRUB package to use.
The output terminals used for the GRUB boot menu, as a list of symbols.
These values are accepted:
pkmodem. This field corresponds to the GRUB
variable GRUB_TERMINAL_OUTPUT (see Simple configuration in GNU
The input terminals used for the GRUB boot menu, as a list of symbols.
The default is the native platform terminal as determined by GRUB at
run-time. These values are accepted:
This field corresponds to the GRUB variable GRUB_TERMINAL_INPUT
(see Simple configuration in GNU GRUB manual).
The serial unit used by GRUB, as an integer from 0 to 3. The default value is chosen by GRUB at run-time; currently GRUB chooses 0, which corresponds to COM1 (see Serial terminal in GNU GRUB manual).
The speed of the serial interface, as an integer. The default value is chosen by GRUB at run-time; currently GRUB chooses 9600 bps (see Serial terminal in GNU GRUB manual).
Should you want to list additional boot menu entries via the
menu-entries field above, you will need to create them with the
menu-entry form. For example, imagine you want to be able to
boot another distro (hard to imagine!), you can define a menu entry
along these lines:
(menu-entry (label "The Other Distro") (linux "/boot/old/vmlinux-2.6.32") (linux-arguments '("root=/dev/sda2")) (initrd "/boot/old/initrd"))
The type of an entry in the GRUB boot menu.
The label to show in the menu—e.g.,
The Linux kernel image to boot, for example:
(file-append linux-libre "/bzImage")
It is also possible to specify a device explicitly in the file path using GRUB’s device naming convention (see Naming convention in GNU GRUB manual), for example:
If the device is specified explicitly as above, then the
field is ignored entirely.
The list of extra Linux kernel command-line arguments—e.g.,
A G-Expression or string denoting the file name of the initial RAM disk to use (see G-Expressions).
The device where the kernel and initrd are to be found—i.e., the GRUB root for this menu entry (see root in GNU GRUB manual).
This may be a file system label (a string), a file system UUID (a
bytevector, see File Systems), or
#f, in which case GRUB will
search the device containing the file specified by the
field (see search in GNU GRUB manual). It must not be
an OS device name such as /dev/sda1.
The mount point of the above device on the system. You probably do not need to change the default value. GuixSD uses it to strip the prefix of store file names for systems where /gnu or /gnu/store is on a separate partition.
Themes are created using the
grub-theme form, which is not
This is the default GRUB theme used by the operating system, with a fancy background image displaying the GNU and Guix logos.