x86: Adding Kernel Arguments by Editing the GRUB Menu at Boot Time

On x86 platforms, you can set boot attributes and kernel arguments for a specific boot entry by editing the GRUB menu at boot time. These changes persist until the next time the system is booted.

To permanently set boot attributes for a specific boot entry, use the bootadm command with the change-entry subcommand. See How to Set Attributes for a Specified Boot Entry in the GRUB Menu.

When you boot an x86 based system the GRUB main menu is displayed. This menu contains a list of all of the boot entries that are currently on the system. To edit a specific boot entry, use the arrow keys to select the entry, then type e to edit the entry. In the GRUB edit screen, navigate to the $multiboot line, then type the additional boot option or kernel argument at the end of the line.

The $multiboot line in the GRUB edit menu might look similar to the following:

$multiboot /ROOT/transition/@/$kern $kern -B console=graphics -B $zfs_bootfs

For example, to disable the e1000g network driver and load kmdb at boot time, you would edit the GRUB menu for the specified entry, as follows:

$multiboot /ROOT/solaris/@/$kern $kern -B disable-e1000g=true -k -B $zfs_bootfs

To exit the GRUB edit menu and boot the entry you just edited, press Control-X. If you have a system with UEFI firmware, and you are not using a serial console, pressing F10 also boots the entry.

The following kernel arguments and options can be specified when you edit the GRUB menu at boot time:

unix

Specifies the kernel to boot.

–a

Prompts the user for configuration information.

–i altinit

Specifies an alternative executable as the primordial process. altinit is a valid path to an executable.

–k

Boots the system with the kernel debugger enabled

–m smf-options

Controls the boot behavior of the Service Management Facility (SMF)

There are two categories of options: recovery options and messages options.

–r

Specifies a reconfiguration boot.

The system probes all attached hardware devices and then assigns nodes in the file system to represent only those devices that are actually found.

–s

Boots the system to a single-user state.

–v

Boots the system with verbose messages enabled.

For more information, see the kernel(1M) man page.