I recently bought a Pinebook Pro. This was mainly out of general interest, but also because I wanted to have a spare portable computer. When I was recently having some difficulty with my laptop not charging, I realised that I am dependent on having access to Emacs, notmuch.el and my usual git repositories in the way that most people are dependent on their smartphones – all the info I need to get things done is in there, and it’s very disabling not to have it. So, good to have a spare.

I decided to get the machine running the hard way, and have been working to add a facility to install the device-specific bootloader to Consfigurator. It has been good to learn about how ARM machines boot. The only really hard part turned out to be coming up with the right abstractions within Consfigurator, thanks to the hard work of the Debian U-Boot maintainers. This left me with a chroot and a corresponding disk image, properly partitioned and with the bootloader installed. It was only then that the difficulties began: getting a kernel and initrd combination which can output to the Pinebook Pro’s screen and take input from its keyboard is not really straightforward yet, but that’s required for inputting disk encryption passwords, which are required on portable devices. I don’t have the right hardware to make a serial connection to the machine, so all this took a lot of trial and error. I’ve ended up using Manjaro’s patched upstream kernel build for now, because that compiles in the right drivers, and debugging an initrd without a serial connection is far too inefficient.

What I keep having to remind myself is that this device isn’t really a laptop in the usual sense – it’s a single board computer that’s powering several pieces of hardware which together roughly constitute a laptop. I think something which epitomises this is how the power light doesn’t come on when you hit the power button, but only when the bootloader or operating system kernel thinks to turn on the LED. You start up this SBC and it loads up some software and then once it has got itself going – several seconds later – that software starts turning on the screen, keyboard, power LEDs etc. Whereas on an ordinary laptop it’s more than you turn on the keyboard, screen, power LEDs etc. all at once, and then /they/ go off and load some software. Of course this description is nothing like what’s actually going on, but it’s my attempt to capture how it feels as a user, who is installing operating systems, but otherwise treating the laptop’s hardware, including things like boot ROMs, as a black box. There are tangible differences between what it is like to do that with an ordinary laptop and with the Pinebook Pro.

Thanks to Vagrant Cascadian for all the work on U-Boot in Debian and for help on IRC, Cyril Brulebois for help with crossbuilding, and Birger Schacht for a useful blog post.