Is it possible to conduct a Debian install over wifi (iwlwifi)?

[Andy Smith <andy@strugglers.net>]

Hi,

I've got a ThinkPad X1 Carbon gen 4 which I'd like to try installing
Debian on. Preferably stable, but I'll try with testing if
necessary.

The machine has an Intel 8260 wifi which will require non-free
firmware. Although it has an eth0 (e1000e), physically using that
requires an adaptor, so that is not an option.

As per
http://cdimage.debian.org/cdimage/unofficial/non-free/cd-including-firmware/
I wrote an ISO of the current amd64 netinst including non-free
firmware to a USB and booted from it.

At no point does it tell me that it requires additional firmware. It
also does not load iwlwifi or any of the associated wifi modules.

So, given this is a netinst installer I am unable to proceed.

I tried dropping to a shell and doing "modprobe iwlwifi". Although
this appeared to load the module without error (lsmod shows it), it
did not result in a wlan0 network device appearing.

Is there any way to force the debian-installer to realise it needs
to load firmware for this wifi device? I have a feeling that it is
seeing there is an eth0 and giving up at that point, assuming that
is good enough.

All of my online research so far just shows instructions that say
that the installer will ask for firmware if it thinks it needs it.

Is it even possible to do a Debian install over wifi alone?

I've booted an Ubuntu live environment and the wifi does work there,
so am pretty sure it's just a driver/firmware issue.

Cheers,
Andy