+ - Start your system and wait for the GRUB menu to show (if you don't see a GRUB menu, press and hold the left <​key>​Shift</​key>​ key right after starting the system).
+ - Now highlight the kernel you want to use, and press the <​key>​e</​key>​ key. You should be able to see and edit the commands associated with the highlighted kernel.
+ - Go down to the line starting with **linux** and add your parameter **foo=bar** to its end.
+ - Now press <​key>​Ctrl</​key>​ + <​key>​x</​key>​ to boot.
+ - Find the line starting with **GRUB_CMDLINE_LINUX_DEFAULT** and append **foo=bar** to its end. For example: **GRUB_CMDLINE_LINUX_DEFAULT="​quiet splash foo=bar"​**. Save the file and close the editor.
+ - Finally, start a terminal and run: **sudo update-grub** to update GRUB's configuration file (you probably need to enter your password).
+ On the next reboot, the kernel should be started with the boot parameter. To permanently remove it, simply remove the parameter from **GRUB_CMDLINE_LINUX_DEFAULT** and run **sudo update-grub** again.