This post originated from an RSS feed registered with Python Buzz by Aaron Brady. Original Post: Void Linux CDC Ethernet on the Raspberry Pi Zero Feed Title: insom.me.uk Feed URL: http://feeds2.feedburner.com/insommeuk Feed Description: Posts related to using Python. Some tricks and tips, observations, hacks, and the Brand New Things. Latest Python Buzz Posts Latest Python Buzz Posts by Aaron Brady Latest Posts From insom.me.uk

A quick howto. Void Linux is a minimal Linux distribution that aggressively tracks upstream software with a rolling release model. They use runit as their init and have the option to use musl as their libc.

Binaries are available for x86_64 and ARM platforms, with a distribution available for the Raspberry Pi 1 (which is close enough to the Zero).

Unfortunately, it looks like the default Pi build expects you to have a console and keyboard on the machine. As I only have a serial terminal, the first thing that I did was set it up to print console messages to the built-in UART, and set up a getty on /dev/ttyACM0.

Follow the installation instructions, and while you have the filesystem mounted, change boot/cmdline.txt to:

root=/dev/mmcblk0p2 rw rootwait console=ttyAMA0,115200 kgdboc=ttyAMA0,115200 smsc95xx.turbo_mode=N dwc_otg.lpm_enable=0 loglevel=4 elevator=noop

That will take care of the boot messages. To be able to actually log in, we’re going to need to change to etc/runsvdir/default (relative to your mount-point, /mnt/rootfs for me) and create a symbolic link to a file which won’t actually exist for you:

ln -sf /etc/sv/agetty-ttyAMA0

That’s going to make sure that a getty on ttyAMA0 loads on boot. This was already included in the distribution, it just wasn’t enabled by default.

The next step was enabling CDC Ethernet – I think that this is one of the best features of the Zero, you can have a little computer that you plug in with a Micro USB lead and you can SSH straight to it.

To make the module load at boot time create the modules-load.d folder and list the modules in the order that we need them (dwc2 for gadget support, g_ether for CDC Ethernet support)

mkdir -p etc/modules-load.d
tee etc/modules-load.d/ether.conf << EOF
dwc2
g_ether
EOF

Because I like the device to always get the same DHCP lease and show up as the same network device when plugged into my laptop, I also set the host and device addresses:

tee etc/modprobe.d/ether.conf << EOF
options g_ether host_addr=32:70:05:18:ff:78 dev_addr=46:10:3a:b3:af:d9
EOF

Finally, I make sure that the Zero will DHCP for this new network device the first time that I plug it in:

cd etc/sv
cp -r dhcpcd-eth0 dhcpcd-usb0
ex dhcpcd-usb0/run
:%s/eth0/usb0/g
:wq
cd ../../etc/runit/runsvdir/default
rm dhcpcd
ln -sf /etc/sv/dhcpcd-usb0 # this absolute path won't exist yet

That’s it for the Zero, just unmount the filesystems and pop the MicroSD card into your Raspberry Pi.

I use Ubuntu on my laptop, so when I plugged in my Zero, it detected a new network device. Select ‘Edit Connections…’ in the Network Manager applet to reconfigure this new USB device that has shown up - you’ll want to go to ‘IPv4 Settings’ and then choose ‘Shared to other computers’. Okay your way out an wait a few seconds for everything to catch up.

The IP address of your Zero should in /var/lib/misc/dnsmasq.leases – SSH in and enjoy!