How can i tell if it's unlocked?
Ah, when you boot up, you'll not only see an icon/symbol of an unlocked pad lock, but you'll also get a boot warning of "
Your device software can't be checked for corruption. Please lock the bootloader. Visit this link on another device: g.co/ABH".
So, if you're not seeing this on boot-up, it's a good bet that it has not been previously unlocked.
Note: unlocking the bootloader will indeed wipe your device--that's a security measure, so be sure that you really want to do so before performing the unlock procedure (i.e., backup your stuff first).
Also, you
MUST go into
Settings ->
Developer options and check/enable
OEM unlocking before you'll be allowed to unlock the bootloader.
If you don't see the
Developer options row in your
Settings screen, you must first go to
About phone and tap
Build number seven times to make that new row appear in
Settings.
The rest of the process will require:
LOL, as I finished typing the above up, I realized that while I consider the above process fairly simple and straightforward, its likely not for others. There is the
Nexus Root Toolkit that can/will/does automate the above process (
after enabling
OEM unlocking)--I typically don't remember to mention it because I do the steps manually (since I want to know the actual steps that are being performed).
Anyway, I'll stop here to let you decide how (and if) you'd like to proceed (there's a bit more of the manual, detailed steps I'd have to list vs. what the NRT will do for you.
Cheers!