I was trying to flash my nexus 7 (2012) with Android L but failed to do so as fastboot couldn’t find my devices. I thought it was Multirom etc which I had on my device causing problem. It turned out that my ubuntu was unable to identify the device specifically for fastboot. Here is how I got this sorted.
# reboot into fastboot mode
adb reboot bootloader# grab you fastboot/bootloader device ids
lsusb
> Bus 001 Device 035: ID **18d1:4e41** Google Inc.# install the ids into /etc/udev/rules.d/99-android.rules
SUBSYSTEM==”usb”, ATTR{idVendor}==”18d1″, ATTR{idProduct}==”4e41“, MODE=”0666″, OWNER=”thiago” # restart udev
/etc/init.d/udev restart
# try fastboot (only on bootloader mode)
fastboot devices
