When we reproduced this, it was with the grub2 build in xenial.
Are you booting with or without secureboot enabled, and with or without a signed kernel? This would make a difference to which entry point grub uses into the kernel, which does impact how kernel early boot does video setup.
When we reproduced this, it was with the grub2 build in xenial.
Are you booting with or without secureboot enabled, and with or without a signed kernel? This would make a difference to which entry point grub uses into the kernel, which does impact how kernel early boot does video setup.