I could fix this on my computer like this:
Summary: In /etc/default/grub, I edit the options so that plymouth is not used.
Details:
sudo nano /etc/default/grub
Then: edit the following parameter to the new value noplymouth
GRUB_CMDLINE_LINUX_DEFAULT="noplymouth"
After that, you must run update-grub: sudo update-grub
Result: Plymouth is not used any more at startup and you can enter the passphrase in text mode.
I could fix this on my computer like this:
Summary:
In /etc/default/grub, I edit the options so that plymouth is not used.
Details:
sudo nano /etc/default/grub
Then: edit the following parameter to the new value noplymouth
GRUB_CMDLINE_ LINUX_DEFAULT= "noplymouth"
After that, you must run update-grub:
sudo update-grub
Result: Plymouth is not used any more at startup and you can enter the passphrase in text mode.