Comment # 4 on bug 1219180 from Thomas Zimmermann

(In reply to Fabian Vogt from comment #3)
> (In reply to Thomas Zimmermann from comment #2)
> > This uses virtio_gpu. I assume it runs in an emulator or virtual machine?
> 
> Correct. Other emulated hardware didn't work either (IIRC -vga std)

VGA requires a VGA BIOS, which is x86 code.

Under regular aarch64 systems (e.g., Rpi) the firmware's framebuffer is listed
in the device tree. But there is no DT here; just UEFI. 

I've installed MicroOS in Aarch64 qemu to test. The kernel config is correct.
There is some support for graphics in the early boot stages (GRUB).