I made a mistake while trying to flash an stock rom in my XT1644. While unlocking bootloader, I didn't realize I had to check the "allow OEM unlock" in developer options. When I thought unlocking had gone good, I started flashing manually a stock update, and everything failed. Now, I can't boot into recovery nor flash a recover nor unlock correctly bootloader, since "allow OEM unlock" still appears on screen.

Tried using RSD Lite, but doesn't work.

How can I unlock my device without checking the "allow OEM unlock" since I have no OS nor recovery?

  • You can't unlock it without that turned on. You need to get the proper stock rom and flash via fastboot.
    – acejavelin
    Mar 24, 2017 at 0:47
  • I know, and that's precisely the problem, that I can't boot anything since I broke it all. Should I do hardbrick maybe?
    – sant016
    Mar 24, 2017 at 1:06
  • If it doesn't show up as a QLoad device, you can't... it's not hard-bricked. You need to get the stock ROM flashed with fastboot. Are you doing it manually with fastboot oem fb_mode_set, flash bootloader and gpt.bin, then fastboot reboot-bootloader and continue through rest of options? If that won't work, I got nothing. What did you flash incorrect? If it was a bootloader or partition table (gpt.bin) you may have perma-bricked it.
    – acejavelin
    Mar 24, 2017 at 3:05
  • I haven't done fastboot reboot-bootloader, but always doing fastboot flash partition gpt and fastboot flash bootloader bootloader.img fails. I just simply thought the device was unlocked and flashed gpt.bin, not being able to boot recovery neither rom since that.
    – sant016
    Mar 24, 2017 at 3:45
  • 1
    "Preflash validation failed" means the factory image you are using is older than your current software... you cannot downgrade, you need to find the same or newer firmware image that matches your device.
    – acejavelin
    Mar 24, 2017 at 18:06

1 Answer 1


Hmm... You need to wipe everything so that system does not interfere in the process of flashing a new rom.

fastboot -> fastboot device. it should show your device. keep following ready : XT1644 Stock Marshmallow/Nougat Image Sparsechunk ZIP. I will post link in next edit. Keep commands ready. When flashing, omit flashing OEM command. start flashing with Partition.gpt.

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