How to modify GRUB
Step 1:
When GRUB start, press any keys and it will show you a boot menu.
Step 2:
In the menu, you can select the kernel to boot and press "e"
Step 3: You will see something like this on the screen
grub append > ro root=LABEL=/ rhgb quiet
Step 4a: Put in the necessary parameters. For example, if I wish to boot to "single"
grub append > ro root=LABEL=/ single
Step 4b: If I wish to boot into console with network support, use the parameter: init=/sbin/init 3
grub append > ro root=LABEL=/ init=/sbin/init 3
Step 4c: If I wish to specify the memory, use the parameters: mem=MEMORY_SIZE
grub append > ro root=LABEL=/ mem=1024M
Step 4d: If you wish to reboot the kernel after the kernel panic, you can set the parameter panic=SECOND
grub append > ro root=LABEL=/ panic=30
For more parameters, do read the excellent article on
