How do I "edit grub to add iomem=relaxed"?

Question

• Ubuntu 18.04 64bit
• libreboot
• flashrom 0.99

The matter is beyond my skills.

I want to flash libreboot on a gigabyte mainboard.

I got the ROM file, renamed it to libreboot.rom and tnstalled flashrom.
Then I ran the command

flashrom -p internal:dualbiosindex=0 -w libreboot.rom

But it did not work.

I was told to edit grub to add iomem=relaxed.

At the Ubuntu location Computer > etc > default > grub, the grub file has:

# If you change this file, run 'update-grub' afterwards to update
# /boot/grub/grub.cfg.
# For full documentation of the options in this file, see:
#   info -f grub -n 'Simple configuration'

GRUB_DEFAULT=0
GRUB_TIMEOUT_STYLE=hidden
GRUB_TIMEOUT=10
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=""

# Uncomment to enable BadRAM filtering, modify to suit your needs
# This works with Linux (no patch required) and with any kernel that obtains
# the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...)
#GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef"

# Uncomment to disable graphical terminal (grub-pc only)
#GRUB_TERMINAL=console

# The resolution used on graphical terminal
# note that you can use only modes which your graphic card supports via VBE
# you can see them in real GRUB with the command `vbeinfo'
#GRUB_GFXMODE=640x480

# Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux
#GRUB_DISABLE_LINUX_UUID=true

# Uncomment to disable generation of recovery mode menu entries
#GRUB_DISABLE_RECOVERY="true"

# Uncomment to get a beep at grub start
#GRUB_INIT_TUNE="480 440 1"

Shall I edit

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

into

GRUB_CMDLINE_LINUX_DEFAULT="iomem=relaxed quiet splash"

with nano?

Solution

You can use nano but personally I do everything with gedit both in my regular user account and with sudo. In this case sudo is needed so it would be:

sudo -H gedit /etc/default/grub

Then change:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

to:

GRUB_CMDLINE_LINUX_DEFAULT="iomem=relaxed quiet splash"

• Save the file
• Exit gedit
• Run sudo update-grub
• Type reboot

After rebooting type:

cat /proc/cmdline

You will see your changes in effect. Whether everything works or not is a different story :)

Comments

[Pavel Sayekat]

Yes, exactly like that.