Fastboot on ubuntu can't find devices

1. Open a terminal window.
2. Log in as root.

sudo -i

3. Create a UDEV rule file.

cat > /etc/udev/rules.d/51-android.rules

This should give you a blinking cursor at the very beginning of a blank line, it’s waiting for you to tell it what the file needs to contain.

4. Enter this AFTER YOU REPLACE “XXXX” WITH YOUR VENDORID:

SUBSYSTEM=="usb", SYSFS{idVendor}=="XXXX", MODE="0666"

(You can find your vendor ID on this page.
For example, for my Dell Streak, I would use:

SUBSYSTEM=="usb", SYSFS{idVendor}=="413c", MODE="0666")

5. Press CTRL + D to save, it should return you to the terminal prompt

6. chmod the new file

chmod a+r /etc/udev/rules.d/51-android.rules

7. Reboot system

8. Try fastboot. It should work now.

fastboot devices