Android fastboot waiting for devices

The short version of the page linked by D Shu (and without the horrible popover ads) is that this "waiting for device" problem happens when the USB device node is not accessible to your current user. The USB id is different in fastboot mode, so you can easily have permission to it in adb but not in fastboot.

To fix it (on Ubuntu; other systems may be slightly different):

Run lsusb -v | less and find the relevant section which will look something like this:

Bus 001 Device 027: ID 18d1:4e30 Google Inc. Couldn't open device, some information will be missingDevice Descriptor:...  idVendor           0x18d1 Google Inc.

Now do

sudo vi /etc/udev/rules.d/11-android.rules

it's ok if that file does not yet exist; create it with a line like this, inserting your own username and vendor id:

SUBSYSTEMS=="usb", ATTRS{idVendor}=="18d1", MODE="0640", OWNER="mbp"

then

sudo service udev restart

then verify the device node permissions have changed:

ls -Rl /dev/bus/usb

The even shorter cheesy version is to just run fastboot as root. But then you need to run every command that talks to the device as root, which tends to cause other complications. Simpler just to fix the permissions in the long run.

Just use sudo, fast boot needs Root Permission

To use the fastboot command you first need to put your device in fastboot mode:

$ adb reboot bootloader

Once the device is in fastboot mode, you can boot it with your own kernel, for example:

$ fastboot boot myboot.img

The above will only boot your kernel once and the old kernel will be used again when you reboot the device. To replace the kernel on the device, you will need to flash it to the device:

$ fastboot flash boot myboot.img

Hope that helps.