HP Laptop Keyboard Not Working At Boot Start
Original article is for Linux Mint, but this affects Ubuntu as well.
This disables the caps lock indicator.
sudo vi /etc/default/grub
Update the GRUB command line to include the i8042 entry, e.g.:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash i8042.dumbkbd=1"
Save the file, then run sudo update-grub
and reboot.