Warn about (or outright disable) apt-get upgrade

[nf]

If you run apt-get update && apt-get upgrade on your norns it will hose the custom kernel and related things that are required to drive the norns hardware (including the usb ports, and therefore wifi). To get out of this state requires you to rewrite the filesystem which is an annoyance.

It would be good if we could warn about, or even entirely prevent, this particular foot-gun. :-)

[tehn]

will investigate pinning the version number of the kernel so apt-get won't mess with it (as suggested by @simonvanderveldt )

[simonvanderveldt]

I've made a PR to norns-image to add this https://github.com/monome/norns-image/pull/57 We should probably include the same thing in the next update. Note I see this as a temporary measure, we should make our own proper kernel package which replaces the upstream kernel package, I've created an issue for that https://github.com/monome/linux/issues/10

And finally: @tehn maybe we could/should merge the norns-image stuff into this repo? Not sure it makes sense to maintain multiple repos for this?

[artfwo]

please let's not merge norns-image with norns, since the latter can be built on other systems too and norns-image is a bunch of raspbian-specific setup scripts among other things.

[tehn]

let's open a separate issue if we want to continue discussing repo merging