This might help with those long boot times. Flip done timed out - May 26, 2018 -
I should’a made a note of this when it first happened on 16.04. Same fix - add video=SVIDEO-1:d in grub. See -
And also see -
From the first Askubuntu post: This is a bug. To avoid delay you can use a workaround. From your terminal run:
sudo pluma /etc/default/grub
Then add the kernel boot parameter: video=SVIDEO-1:d, so it will look like this:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video=SVIDEO-1:d"
Then
sudo update-grub
sudo reboot
No more flip done timed out messages, drastically shorter boot times.