Plymouth taking a lot of time during boot

Question

 $ systemd-analyze blame

     3min 19.728s plymouth-quit-wait.service
     19.248s dev-sda4.device
     13.448s systemd-udevd.service
      6.593s NetworkManager-wait-online.service
      4.702s snapd.service
      4.262s networking.service
      3.733s fwupd.service
      3.149s irqbalance.service
      2.981s apport.service
      2.484s NetworkManager.service
      2.338s grub-common.service
      2.322s speech-dispatcher.service
      2.321s ondemand.service
      2.240s accounts-daemon.service
      1.518s keyboard-setup.service
      1.246s systemd-tmpfiles-setup.service
      1.212s systemd-tmpfiles-setup-dev.service
      1.165s apparmor.service
      1.065s systemd-modules-load.service
       966ms systemd-journald.service

Answer 1

You can remove plymouth during your boot up process and display progress messages by using:

sudo -H gedit /etc/default/grub

Find the line containing:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

and remove quiet splash between the double quotes. If you have additional parameters leave them as is.

Save the file and run:

sudo update-grub

Then reboot and watch the messages that appear for any clues on what is causing delays.

After boot completes run:

systemd-analze blame

once more and report back with the results.