If you're using a Nexus and you like tinkering, know very well the "Fastboot oem unlock" command that allows us to unlock the bootloader of the Nexus device in question them so they can get their hands. With the arrival of Android 5.0 Lollipop, there is little change in the use of this command.
With the new version of Android, if we try to apply this command will always fail unless we have a particular item in the development of terminal options. This is the setting "Enable OEM unlock", the box must be marked or otherwise the command will fail.
9 oem unlock nexus
This is a minor change, a small detail of the many we already know but who will join more as insurance Lollipop go deploying the rest of Nexus. As discussed from AndroidPolice in his unit appeared Nexus 6 this box already checked, but does not have to occur at rest and some users have reported that the Nexus 9 is displayed unchecked and must be activated manually.
In the picture above you can see the specific option we have drawn from our Nexus 9 but the options of development, as in all editions of Android is accessed by pressing the "Number of Compilation" repeatedly must be enabled before.