As soon as I got home after the Android M image was available, I (of course) flashed it to my Nexus 5, following all the usual procedure (e.g. wiping Dalvik and Cache). Now it's been stuck on the flying dot sequence for a long time (20-30 minutes). Has that happened to anyone else?

  • You also need to wipe data for a preview image.
    – Thomas Vos
    Commented May 29, 2015 at 20:14
  • For a major OS upgrade (i.e. new letter) wiping /data is always necessary.
    – user43185
    Commented May 30, 2015 at 17:16
  • Same here and I unlocked the bootloader right before flashing so that would have taken care of wiping it no? Commented Jun 24, 2015 at 22:58

4 Answers 4


I'd be willing to bet you need to do a factory reset, not just a wipe of cache. Generally that's required for the preview images, and if you don't, you end up with exactly what you just reported.

  • Is there a way to fix it? Wipe it via fastboot? Then reflash? Commented Jun 24, 2015 at 22:59

Second the above:

[user@name]:~/hammerhead-MPZ44Q$ fastboot erase userdata
[user@name]:~/hammerhead-MPZ44Q$ fastboot erase cache
[user@name]:~/hammerhead-MPZ44Q$ fastboot erase system
[user@name]:~/hammerhead-MPZ44Q$ fastboot flash system system.img
[user@name]:~/hammerhead-MPZ44Q$ fastboot flash cache cache.img
[user@name]:~/hammerhead-MPZ44Q$ fastboot flash recovery recovery.img
[user@name]:~/hammerhead-MPZ44Q$ fastboot flash userdata userdata.img

should do the trick.

  • I think you should also mention what those commands are doing, at least brief the readers. And do mention that your command would eradicate present user data (including apps, their data, stuff in Internal SD card).
    – Firelord
    Commented Jul 7, 2015 at 17:48

In my case all I had to do was unplug the device from the USB cable, and it finished booting. If it's not you case, you can try: Wiping the cache partition and wiping the the user data (factory reset). You can do it by shutting down the cell phone, booting in fastmode (vol down + power) and selecting recovery. You will have to press power and after 1 second, press volume up to show the recovery menu, where you can do the wipe.


I ran into this issue with my nexus 5 with the Chainfire SuperSU. If you're using that, the short answer is that there's a special boot.img to use. Also, make sure to use a pretty recent SuperSU (i used BETA-SuperSU-v2.50.zip. You can plug the phone into your computer and reboot it into the boot loader and fastboot load the boot image and then also adb sideload the new SuperSU.

Here are the steps I took in more details.

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