How to check if your bootloader is unlocked 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?
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)