I'm about to flash a custom recovery, but I'm not sure if my bootloader is unlocked or not (phone is rooted, but I did it a while ago, so I can't remember the process I went with), and I don't want to do anything that might risk losing all my current data. Can I simply run fastboot flash recovery [recovery image], and if it doesn't work, take that to mean my bootloader is locked? Are there any negative consequences to attempting this with a locked bootloader?

  • You give this a whirl? : forum.xda-developers.com/studio-5/general/… – Enigma Feb 26 '16 at 21:53
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    For some reason my dialer does not accept 15 characters :-(. When I enter the last asterisk it clears the whole field out. – Kash J. Rangan Feb 26 '16 at 22:35
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    That's not an input limitation but the result of having entered the full special code. If you didn't get a popup that means that method won't work on your hardware. – Enigma Feb 26 '16 at 22:55

Assuming your device adheres to some Android standards, you'd want to run fastboot oem device-info.

Often you can also run fastboot reboot-bootloader to get into the bootloader which often says right there on screen whether it's locked or not.

Different devices can display the lock state differently.

fastboot is located in %ANDROID_SDK_DIR%\platform-tools, where the part inside the %...%is where you installed the Android SDK.

Typically though it's not the bootloaders lock state that will result in failed roots. That is usually (depending on your method) due to the /system partition still being locked to read-only mode which has nothing to do with the bootloader IIRC.

An alternative method that may have mixed results:

  • Open your device’s dialer
  • Dial *#*#7378423#*#* and it will automatically open a new window if it works
  • Now in that window go to Service Info > Configuration

You ought to see one of these:

Bootloader unlock allowed - Yes (Bootloader is Locked)

Bootloader Unlocked - Yes (Bootloader is unlocked)

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  • You have my upvote if you can include Samsung's methods. I'm actually curious. – Aaron Gillion Feb 26 '16 at 21:30
  • @AaronGillion I don't touch Samsung devices with a 10 foot stick but often times if it isn't obvious with some sort of unlock icon or an odd message displayed somewhere during boot, it's probably locked. Still I am curious as well about whether that info can be grabbed via command line so I will continue looking for a bit. – Enigma Feb 26 '16 at 21:37
  • Does not work for LGp690 – Calmarius Mar 20 '18 at 16:14

i'm no expert, but if you go to the bootloader, by (on my nexus 4) holding volume down then power up, then it says

enter image description here

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After scouring the net, I've learned this can be determined by entering your device's fastboot mode (from your device's boot menu selection, select AP Fastboot) and about four or five lines down from the top, you should see either Device is LOCKED or Device is UNLOCKED.

Unfortunately I only discovered this after attempting to flash the custom recovery while my bootloader was locked, which would subsequently put it into fastboot mode upon every boot attempt with the message "Fastboot reason: Flash failure". But I got around this by entering boot selection mode (holding vol down, up, and power simultaneously) and selecting "Normal Powerup" at the top. I unlocked my bootloader, flashed again, and am now happily running CyanogenMod 11. Hope this helps someone.

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