ODROID-C1 post-installation tips

Some weeks ago I decided you replace my old and rusty Raspberry Pi (serving as a media center) with something faster (and less likely to suddenly lose ethernet connection). I stumbled over the dirt-cheap ODROID-C1, which outruns the Raspberry Pi (and even the brand-new Raspberry Pi 2) thanks to its Amlogic S805 ARM Quad Core Cortex™-A5 processor and Dual Core Mali-450 GPU. And it’s also supported by ArchLinuxARM.

If you’ve also purchased that little device, here are some solutions to problems I encountered upon first boot (after setting up basic stuff like timezone, hostname, locale, etc.), so I hope that these tips help you, too.

Blacklisting the Dallas 1-Wire interace

In case you’re not going to use the 1-wire interface, you might want to blacklist the kernel module. Otherwise, it’ll keep scanning all day long for attached sensors. Create /etc/modprobe.d/blacklist-w1.conf and insert:

# Disable the 1-wire interface
blacklist w1_gpio

Enabling the Hardware Random Number Generator

Use the hardware RNG instead of haveged. You need to install rng-tools and make sure that /etc/conf.d/rngd contains:

RNGD_OPTS="-o /dev/random -r /dev/hwrng"

Then, you can enable the rngd service via systemd:

$ sudo systemctl stop haveged
$ sudo systemctl start rngd

To keep using the hardware RNG after a reboot:

$ sudo systemctl disable haveged
$ sudo systemctl enable rngd

HDMI-related stuff

Getting video working

If you’ve configured everything correctly, but you still get no image on your display, chances are that you bought a non-standard HDMI cable that misses the group pin. Either go buy another cable (it’s rumoured that the AmazonBasics HDMI-to-Micro-HDMI cable works) or short the shell of the Micro-HDMI with the (grounded) Micro-USB-shell. I used a paperclip to do this. Have a look at this post in the ODROID forum.

Getting audio working

Install pulseaudio. You need to edit Pulseaudio’s default.pa, so either edit /etc/pulse/default.pa in-place or copy it to ~/.config/pulse/default.pa of the respective user.

Search for these lines:

#load-module module-alsa-sink
#load-module module-alsa-source device=hw:1,0

And replace them with:

load-module module-alsa-sink
load-module module-alsa-source device=hw:0,1

Important: Make sure that it’s hw:0,1 and not hw:1,0!

Also, do not forget that your user need to be part of the audio group to use the sound device.

Now you can check if everything worked by running:

$ paplay /usr/share/sounds/alsa/Front_Center.wav 

Getting CEC working

Unfortunately, that’s a hardware issue. The guys at Hardkernel are working on it, so chill. You’ll probably need to RMA your device or do some soldering yourself, though. Check out this thread in the ODROID forum.

Adblock on your router

A lot of people already use Adblockers in their desktop browser, but what if you’re using your phone, tablet or an alternative browser? Getting rid of annoying ads is simple: Block them with your router.

The idea is simple: when the DNS server on your router receives queries, we’ll sort out queries that ask for the A Resource Records of ad servers and return 127.0.0.1 instead of the ad server’s IP address.

There are loads of scripts out there to accomplish something like that. IMHO, some are too complex (like changing the FORWARD chain in iptables), some do stuff I don’t like (e.g. manipulating stuff in /etc/) and some even pose a security threat, because they download config files and use them without checking their content.

This is why I wrote such a script myself. What It does:

  • download a list of ad servers in dnsmasq config file format from yoyo.org
  • check if the file only contains address statements that assign the IP address 127.0.0.1 to some domain name (with grep)
  • save the file as /tmp/dnsmasq.d/adblock.conf
  • restart dnsmasq

You need at least OpenWRT revision 39312 to use it.

Enough talk, let’s get going: Simply SSH to your router, download this script:

# mkdir -p /opt/bin
# curl "https://gist.githubusercontent.com/Holzhaus/ed4ac1675a57f11c3057/raw/6a2b59ce046ad6da5f9eac48db925f0afb292a00/adblockupdater.sh" > /opt/bin/adblockupdater.sh
# chmod +x /opt/bin/adblockupdater.sh
# /opt/bin/adblockupdater.sh

To update the server list on a regular basis, add the line 0 0 */1 * * /opt/bin/adblockupdater.sh to your crontab by typing crontab -e.

Congrats, you now have adblock on your router!

Note: If you can’t download the script, because you’re getting curl: (51) Cert verify failed: BADCERT_NOT_TRUSTED, you’re probably missing CA certificates. Run:

# opkg update
# opkg install ca-certificates

Also check if export SSL_CERT_DIR=/etc/ssl/certs is in your /etc/profile and add it, if neccessary. Run source /etc/profile and retry.

Ogg videos on RPi/Kodi

I recently wanted to play an OGG video on my Raspberry Pi with XBMC (which has been renamed to Kodi recently). Unfortunately, it didn’t work out of the box. This is how I solved the problems.

Problem 1: Ogg video file not recognized.

If you try to open your file by using the file browser in Kodi’s video section, it won’t be displayed. This is because Kodi assumes that files with the *.ogg extension are audio files.

Solving this is easy: Simply rename somefile.ogg to somefile.ogv (somefile.ogm is also possible). For the sake of completeness: Your Ogg audio files can have *.ogg or *.oga as file extension.

Although you can also change the way Kodi detects files and make *.ogg a video file extension, I do not recommend this. That extension is much more common with audio files and renaming Ogg videos to *.ogv makes audio and video files distinguishable by just reading the filename.

Now you can see the Ogg video file in Kodi’s file browser. You hit enter and …. have another problem.

Problem 2: Ogg video file playback is audio-only

Now the file actually plays and you can hear the sound, but there’s no video. This is probably because the RPi’s GPU does not know how to decode the video. GPU accelerated software codecs are only available from start_x.elf.

Open /etc/profile/ and append /opt/vc/bin to your $PATH:

# Set our default path
PATH="/usr/local/sbin:/usr/local/bin:/usr/bin:/opt/vc/bin"

Then add this to your /boot/config.txt:

start_file=start_x.elf
fixup_file=fixup_x.dat

That causes the RPi to load testing versions of the GPU firmware. These enable potentially unstable/not-fully-tested/hacky functionality - currently, using these files instead of the usual fixup.dat/start.elf will cause extra video codecs to become available.[1]

Note that you should set your GPU memory to at least 128 MB:

gpu_mem_256=128 # If you have 256 MB RAM (Model A)
gpu_mem_512=128 # If you have 512 MB RAM (Model B)

Et voilà. Kodi is now able to play Ogg video files (hopefully)!

Welcome

Voilà, there is my new website. Do not expect regular updates.