X won't start after fresh Debian install
 

startx shows "cannot run in framebuffer mode. please specify busIDs"

The graphics is Intel onboard, a comet lake processor with a UHD 630 gpu.

This is my first exclusive EFI install. Normally I use a live Debian install with cinnamon, but I couldn't get the thumb drive to boot.. so I'm using vanilla 10.6 amd64.

Can you be more specific? Exactly what image did you download? How did you install, from what media?

I used "debian-10.6.0-amd64-DVD-1.iso", dd to USB removable drive.

Random thoughts.. as the board is one of those made for W10 only, is the 4.19 kernel up to it or a special driver needed..

You need to install Debian "testing" with the non-free firmware. This will give you a 5.8 kernel that supports Comet Lake. You may also need to install the i915 firmware manually if the installer does not automatically install it.
Ed

Or you could just install the backports kernel in stable for the 5.8 kernel.

Thank you. Ultimately I would prefer Stable + the backport. For now, in order to progress I may try the Testing distribution.
At what point is it clear that the installer isn't doing this and how will I tell?

Does getting the backport for stable need to be left until after the installation or can I incorporate into the installation?

On boot, the kernel will issue a message if the firmware could not be loaded. X will not start without the GPU firmware.
Ed

I am now looking to use this image.

https://cdimage.debian.org/cdimage/u...amd64/iso-dvd/

That should work.
Ed

I think you'll need the newer kernel from backports, and the associated firmware. The easiest way to install them is to put them on the USB drive, or even a different drive, then if the desktop won't load, drop to a root shell and install them using apt, with the path to them. Then reboot, and you should have a desktop. I just edit sources.list to change to Sid, update and upgrade, but I've been running Sid for a long time. It's not for everyone, but it does have the latest kernels and firmware. Staying with Stable is entirely understandable and common, but for new hardware you'll need to use backports. Comet Lake won't run on the 4.19 kernel, but fine on any 5-series kernel.

Firstly, I got 'testing' to work. It runs as it should, even though there's a message when I boot - "firmware: failed to load i915/kbl_dmc_ver1_04." If it's harmless I'll leave it alone.

Then, I set up sources for the Bullseye repositories because nothing sets up at install, I have to do it after because my network is out during install.

Anyway, I can't find my favourite term, 'tilix'. Is 'Bullseye' correct rather than 'testing', and are there less packages here than in stable?

I've included a screenshot of /etc/apt/sources.list

Or maybe related to this message in Gnome-Software..

Installing firmware-misc-nonfree should fix that.

Yes, "bullseye" is right.

Tilix may have been dropped if it were broken or unmaintained. I don't know about Gnome. ;)
Ed

Just answering my own questions, both aren't working properly with testing at the moment, so it's good to be aware of that.