Intel microcode update definitely created same issue for me on Asus Zenbook 14 (UX433F) on 18.04.2 LTS.
Can also confirm the instructions above "add dis_ucode_ldr to the kernel command line (from GRUB if you cannot boot)" worked perfectly for temporary workaround.
This is my fourth Asus, and I've been using Linux since 1997, but I can't remember struggling as much with any other machine/distro combo as with this UX433F on Ubuntu.
Intel microcode update definitely created same issue for me on Asus Zenbook 14 (UX433F) on 18.04.2 LTS.
Can also confirm the instructions above "add dis_ucode_ldr to the kernel command line (from GRUB if you cannot boot)" worked perfectly for temporary workaround.
This is my fourth Asus, and I've been using Linux since 1997, but I can't remember struggling as much with any other machine/distro combo as with this UX433F on Ubuntu.