Google Music on Ubuntu: "Login failed. Could not identify your computer"

Update: Easier fix incoming! Download MusicAlpha for Google Chrome and upload all the music, even on crippled systems like Chrome OS! :D

After installing Ubuntu on my Chromebook, I'm now finally able to upload purchased music to Google Music so I can listen to my music on my PlayStation 3. Oh, wait. "Login failed. Could not identify your computer"? The linked support page is a bad joke: "If you're receiving a 'Login failed. Could not identify your computer.' error, we couldn’t identify your machine." Oh really? Now everything makes sense... It goes on with actually helpful information: "Please note that at this time, virtual machines aren't supported by Music Beta." Unfortunately I'm not running Google Music within a virtual machine. Damn, maybe I should have.

Anyway, after looking around for actual solutions, I found out that Google Music is using my MAC address in order to identify my computer. Although I obviously had a MAC address configured, Google Music only accepts them coming from interfaces named eth* (read, eth0, eth1, ...) but all I have is a WLAN interface named "wlan0".

So, in order to rename the interface, do the following:

1. Make a backup first: sudo cp /etc/udev/rules.d/70-persistent-net.rules /etc/udev/rules.d/70-persistent-net.rules.old
2. Edit the file: /etc/udev/rules.d/70-persistent-net.rules
1. If there's another interface called "eth0", put a # in front of it
2. Search for the interface with the name "wlan0" and replace "wlan0" with "eth0"
3. Save the file
3. Restart your machine: sudo reboot
4. Upload all the music!