install libreboot on gigabyte ga g41m es2l version 1.1

"I require a detailed plan."
libreboot.org is very detailed.
So very detailed in fact that the information there can be used to make this quick-and-dirty script.
Yes it should be better. Yes it makes some assumptions. It's not meant to be run blindly.
It assumes you're installing usqwerty_txtmode.rom which may or may not be the case for you.
So you may need to change the file name for something else in libreboot_r20160907_grub_ga-g41m-es2l.tar.xz.
But it should give an idea of what to do.

#!/bin/bash
set -euo pipefail
#SPDX-License-Identifier: GPL-3.0-or-later

# Make note of MAC address
macaddress=`ifconfig -a | grep HWaddr | sed -e 's/^.*HWaddr //'`

# Make a note of ethernet name
interface=interface=`ip link | awk -F: '$0 !~ "lo|vir|wl|^[^0-9]"{print $2;getline}'`

# Put it in /etc/network/interfaces
cat <> /etc/network/interfaces
source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

auto $interface
iface $interface inet dhcp
hwaddress ether $macaddress
EOF

# Get the GPG key to verify releases
gpg --recv-keys 0x969A979505E8C5B2

# Download libreboot utilities
wget https://www.mirrorservice.org/sites/libreboot.org/release/stable/20160907/libreboot_r20160907_util.tar.xz
wget https://www.mirrorservice.org/sites/libreboot.org/release/stable/20160907/SHA512SUMS
wget https://www.mirrorservice.org/sites/libreboot.org/release/stable/20160907/SHA512SUMS.sig

# Verify GPG signature
gpg --verify SHA512SUMS.sig

# Verify hash
sha512sum -c SHA512SUMS 2>&1 | grep OK

# Extract tarball
tar xf libreboot_r20160907_util.tar.xz
cd libreboot_r20160907_util.tar.xz

# Get ROM
mkdir -p rom/grub
wget https://www.mirrorservice.org/sites/libreboot.org/release/stable/20160907/rom/grub/libreboot_r20160907_grub_ga-g41m-es2l.tar.xz

# Verify hash
sha512sum -c ../SHA512SUMS 2>&1 | grep OK

# Extract tarball
tar xf rom/grub/libreboot_r20160907_grub_ga-g41m-es2l.tar.xz

# On GA-G41M-ES2L, libreboot's default GRUB config has a stupid 1 second timeout
# This make it difficult to select other options on boot
# Adjust timeout to be 30 seconds
./cbfstool/x86_64/cbfstool libreboot_r20160907_grub_ga-g41m-es2l/ga-g41m-es2l_usqwerty_txtmode.rom extract -n grub.cfg -f grub.cfg
sed -i 's/timeout=1/timeout=30/g' grub.cfg
./cbfstool/x86_64/cbfstool libreboot_r20160907_grub_ga-g41m-es2l/ga-g41m-es2l_usqwerty_txtmode.rom remove -n grub.cfg
./cbfstool/x86_64/cbfstool libreboot_r20160907_grub_ga-g41m-es2l/ga-g41m-es2l_usqwerty_txtmode.rom add -n grub.cfg -f grub.cfg -t raw

# Do it!
sudo ./flash update libreboot_r20160907_grub_ga-g41m-es2l/ga-g41m-es2l_usqwerty_txtmode.rom

# One you see it's VERIFIED turn off the computer.
# Not reboot -- sudo shutdown -h now

"If I follow your link I can do all the installing. It is not
required to go to libreboot.org for pieces of information?"

Not really.

"You can install libreboot internally from the computer's system hdd? Which would be easier."

Right; libreboot can be installed using only software. An external method of flashing is only needed if something goes wrong.

"Will your link also work to install libreboot on a t400 from a beaglebone black?"

No. The original flashing (when the proprietary junk is still present) has to be done with an external method and can't be done only with software. Once libreboot is installed future updates can be done via software so you really only have that initial hurdle to get over.

https://linuxconfig.org/how-to-install-missing-ifconfig-command-on-debian-linux

ip address
displayed the same macaddress as on windows.

macaddress=`ifconfig -a | grep HWaddr | sed -e 's/^.*HWaddr //'`
Displays nothing on the command line.

If I install trisquel 7 64bit and update will instructions on
http://dpaste.com/20PTCD9.txt
work?
If I install trisquel 8 64bit and update will instructions on
http://dpaste.com/20PTCD9.txt
work?

As far as I understand, 'ip' is the new 'ifconfig'. 'ip link' is already called later in the script, to define the "interface" variable. Its output includes the MAC address too. In other terms, both "interface" and "macaddress" variables can be defined from the output of 'ip link'. For instance:
device=$(ip -o link | grep -ve lo -e vir -e wl)
interface=$(printf "$device" | cut -d : -f 2)
macaddress=$(printf "$device" | grep -Eo '([0-9a-f]{2}:){5}[0-9a-f]{2} ')
I have not used the more complicated 'sed' and 'awk' commands. There is little need for them here. And I preferred 'printf' to 'echo', which is less portable (this choice is pointless if the shebang is not substituted for "#!/bin/sh").