Intro

I have finally received my Kickstarter-backed UP boards. So far they seem great! There are three minor drawbacks, though:

  1. They don't have the exact same shape as Raspberry PI's, so they don't fit the raspberry cases. It's nothing that could not be rectified with small pliers, though.
  2. The audio chip on Cherry Trail (Intel Atom x5 z8350) SoCs is not yet supported by Linux out of the box, so some fiddling with the kernel is necessary.
  3. Debian's UEFI boot configuration does not seem to work from the get-go either.

Boot

You can install Debian Testing using a USB stick. Don't try Jessie, though - the kernel will not detect the MMC card. Things should work fine, except that grub will install itself in /EFI/debian/grubx64.efi on the EFI partition. You will need to move it to /EFI/boot/bootx64.efi manually. It's possible to do it from the UEFI shell using familiar commands.

Media

Kodi installs and works out of the box from Debian Multimedia. Unfortunately, to get the sound working, you will need to recompile the kernel :)

Get the sources and the necessary patches and create the config:

git clone https://github.com/torvalds/linux.git
cd linux
git remote add cht https://github.com/plbossart/sound.git
git fetch cht
git checkout byt-cht-hdmi-v4.7
make oldconfig

You will need to edit .config:

  • to set CONFIG_SYSTEM_TRUSTED_KEYS variable to an empty string
  • to enable CONFIG_HDMI

Then the only thing that's left is building and installing the package:

fakeroot make-kpkg --initrd --append-to-version=-up --revision=1 -j 8 kernel_image kernel_headers
cd ..
sudo dpkg -i linux-image-4.7.0-up+_1_amd64.deb

I wanted to see how efficient it is, so I run the compilation on the board itself. It took roughly 2.5 hours and got very hot. The board can handle perfectly fine the FullHD video files over Samba that Raspberry PI 2 couldn't. The audio quality is much better too. It seems that surround 5.1 actually works. :)

Note 09.11.2017: These drivers have been included into mainline since kernel 4.11. However, you will still need to edit your Alsa settings to choose the default output device. This has worked for me:

]==> cat /etc/asound.conf
defaults.pcm.!card Audio
defaults.ctl.!card Audio
defaults.pcm.!device 2
defaults.ctl.!device 2
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