sudo nano /etc/default/grub
Add the nomodeset parameter so it is "quiet splash nomodeset":
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nomodeset"
Then, ctrl+x to exit, the y
key to say Yes to Save, then the enter
key to save current configuration.
The terminal will revert to normal - now, run sudo update-grub
and the parameter will be permanent.