I want to start the Recovery mode on an Ubuntu-only machine. The problem is that machine seems to skip grub and boot directly into ubuntu (as it is the only OS installed.
How can I boot into the recovery mode (whether it is through GRUB or not)
According to this, holding the Shift key while booting should bring up the GRUB menu. If the Shift doesn't work, repeatedly pressing the Esc may work.
If you enter BIOS (normally F2) first and then exit choosing
EXIT WITHOUT SAVING or similar, you will be prompted with the GRUB menu.
I once, not in the purpose of getting into grub (actually I was measuring the time it takes for Ubuntu to boot), did this and successfully accessed grub menu: Boot up your computer by pressing the power key While it's booting, long press on the power key to turn it off (I am not sure if it is a very safe way to get into grub) Turn it on again with the power key, and... Voila! Here you are at the grub menu. ;) You're welcome!