If the machine encounters an unexpected loss of power, upon the next boot it may present a text-based GRUB boot loader screen. To bypass this, connect a USB keyboard to the top of the tablet and press Enter on the first selection.
To bypass the screen permanently, follow this article. However, this error screen serves as an indication of an improper shutdown that should be avoided.
Connect a USB keyboard, then press Ctrl+Alt+T to bring up a terminal window.
Then enter the root password (provided separately).
Add to the file the following line, without any preceding #:
Press Ctrl+X, type Y, hit Enter.
Press Alt-F4 to close the terminal window and disconnect the keyboard.