In the GRUB boot menu, use the arrow keys to highlight the required kernel and press the space bar.

Figure 3.1 shows the GRUB menu with the UEK selected.

Figure 3.1 GRUB Menu with the UEK selected

Click to view larger image selectkernel.png

Press E to edit the boot configuration for the kernel.

Use the arrow keys to scroll down the screen until the cursor is at the start of the boot configuration line for the kernel, which starts linux16.

Edit the line to change the boot parameters.

For example, press End to go to the end of the line, and enter an additional boot parameter.

Figure 3.2 shows the kernel boot line with the additional parameter systemd.target=runlevel1.target, which starts the rescue shell.

Figure 3.2 Kernel Boot Line with an Additional Parameter to Select the Rescue Shell

Press Ctrl+X to boot the system.