[coreboot] Lenovo X60: GRUB_GFXMODE=1024x768 only works with docking station connected

[Paul Menzel]

Dear coreboot folks,

on the Lenovo X60s, running coreboot with SeaBIOS as payload, adding the
two lines below to GRUB’s configuration in `/etc/default/grub`

GRUB_GFXMODE=1024x768
        GRUB_GFXPAYLOAD_LINUX=keep

and running `update-grub`, which updates GRUB 2.02~beta2-20 (Debian
Jessie/testing) in the MBR, it does only work, when the laptop is
attached to the docking station (nothing attached to the docking
station).

Those of you with a Lenovo system, could you please try to reproduce
this? Also if you still have the vendor firmware, it’d be great to get
some data points. Any hints, how to debug this issue are also
appreciated.

Thanks,

Paul