I just tested a Xubuntu 14.04 x64 LTS upgrade to Xubuntu 16.04. The value:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
is correct for Xubuntu. That is what causes the boot process to have the GUI screen rather than text console messages.
So note to the upgrade package maintainers... it needs to be smart enough to detect/differentiate between Ubuntu Server vs Ubuntu LTS upgrades and select the correct value.
I just tested a Xubuntu 14.04 x64 LTS upgrade to Xubuntu 16.04. The value: LINUX_DEFAULT= "quiet splash"
GRUB_CMDLINE_
is correct for Xubuntu. That is what causes the boot process to have the GUI screen rather than text console messages.
So note to the upgrade package maintainers... it needs to be smart enough to detect/ differentiate between Ubuntu Server vs Ubuntu LTS upgrades and select the correct value.