Sorry, I should have included more detail.
My machine was purchased from Minifree, so no non-free firmware is
required. I run Debian GNU/Linux with only the main repository enabled
and all hardware works.
$ sudo lshw -c video
*-display:0
description: VGA compatible controller
product: Mobile 4 Series Chipset Integrated Graphics Controller
vendor: Intel Corporation
physical id: 2
bus info: pci@0000:00:02.0
version: 07
width: 64 bits
clock: 33MHz
capabilities: msi pm vga_controller bus_master cap_list rom
configuration: driver=i915 latency=0
resources: irq:29 memory:e1000000-e13fffff
memory:d0000000-dfffffff ioport:5400(size=8)
*-display:1 UNCLAIMED
description: Display controller
product: Mobile 4 Series Chipset Integrated Graphics Controller
vendor: Intel Corporation
physical id: 2.1
bus info: pci@0000:00:02.1
version: 07
width: 64 bits
clock: 33MHz
capabilities: pm cap_list
configuration: latency=0
resources: memory:e5500000-e55fffff
Linux kernel is 4.5.4-1, although this is probably irrelevant: The lack
of video precedes the loading of the kernel since from power-on to
desktop there is no video (i.e., there is no libreboot grub menu).
