Comment 6 for bug 1375435

Yes, this does seem to be a duplicate of https://bugs.launchpad.net/ubuntu/+source/plymouth/+bug/1359689.

I tried their suggested workaround and it worked for me, or at least it now boots in text mode and prompts for the password successfully every boot.

For posterity sake, here was the fix/workaround required:

$ sudo nano /etc/default/grub

Include the following parameter

GRUB_GFXPAYLOAD_LINUX=wxh

$ sudo update-grub