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From the Android Forums: Unlocking and root

Justiceanthony asks in the Android Central Forums:

Hi all,I'm new here. I'm looking to buy a new Note 2 for the third time (yeah, I lost the first one and gave the second to my girlfriend). Someone is selling one to me here in Ghana , and it was previously locked to O2 (UK network), it's now been unlocked and my question is whether it's been automatically rooted since it's unlocked. I wouldn't mind a rooted phone since I would like a little more "freedom" . thnx to you all.

First things first -- welcome to AC justiceanthony!

Now to the question. No, SIM unlocking a Note 2 (or any Android phone) does not automatically root it. SIM unlocking is a built-in tool that uses a key to activate. It's done outside of any modification to the firmware, like rooting. Having said that, sometimes the opposite is true, and a root method that unlocks the bootloader will also SIM unlock the phone.

This begs for an explanation about the different uses of the word unlock and root. Lets do that.

Root: Rooting an Android phone is simply adding a file to the system that allows other apps to elevate their permissions and read, write, and execute anything on your device. In this case, anything means anything -- if it is user editable or actionable, you can do it with root. This is both powerful and dangerous, so be sure to get all the answers and be clear on the subject before you do it.

SIM or Network Unlocking: This allows a phone bought for use on a particular network to be used on another network. If you buy a phone designed to only work on Orange (or AT&T for an American example), to use it on any other network, you will need to unlock the SIM programming. This is what Justiceanthony has done in the example above, as he wants to use an O2 phone on his carrier in Ghana. It's done without rooting or modifying any firmware in your phone or tablet.

Remember, the networks have to be compatible. A phone with radios designed for one carrier may not provide 3G or 4G service on another, and sometimes they won't work at all.

Bootloader Unlocking: All Android devices ship with a locked bootloader. Some are very easy to unlock, like Nexus devices, some need a little hacking to unlock (like most Samsung devices), and some are encrypted and designed to be very difficult to unlock (hello, Moto). Bootloader unlocking allows you to flash (write to your phone's "hard drive") image files that haven't been signed with the official key from the folks who made your phone or tablet. A locked bootloader can flash a new recovery provided in an OTA update because the recovery was signed with the right key. It will fail to flash a custom recovery like ClockWorkMod. An unlocked bootloader will flash anything that fits, as long as you tell it to. Once a custom recovery (or sometimes a "Super" boot image) is flashed, you can install and erase custom built system firmware at will. Again, this means you need to do your homework before you start fiddling with things. Use the forums. Read, ask questions, and read some more.

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Jerry Hildenbrand
Senior Editor — Google Ecosystem

Jerry is an amateur woodworker and struggling shade tree mechanic. There's nothing he can't take apart, but many things he can't reassemble. You'll find him writing and speaking his loud opinion on Android Central and occasionally on Twitter.

  • nice read. people tent to confuse between Sim unlocking, bootloader unlocking and rooting. hopefully this is helpful for some.
  • Definitely an awesome read. I've been flashing every device so far but I never really understood bootloader unlocking vs root and superuser.
  • good read for the noobs! I'd say for those who are computer savvy but don't know Android best way to think of the bootloader is the equivalent of the BIOS on a motherboard. The ROM flashing is changing the OS, rooting it like becoming the administrator account on the machine and SIM unlocking is letting you freely choose your ISP.
  • It was very clear and easy to understand...Thank You
  • Well written (concise yet clear) and inspired topic. Keep up the good work, Jerry!
  • Samsung devices are selling with bootloader unlocked in Europe.
  • if you are looking to download android apps, check out
  • problem username&password
  • please some one help me i updated my phones firmware,prl,profile and after i lost my roaming network sent it to the roaming service providers who unlocked it for me with CDMA service now i have no service and they told me is really strange...i am really sad someone help me please what do i do??
  • Thanks for the info. Now a question: If I root an already SIM unlocked device, will it stay SIM unlocked? i.e. will I be able to continue to use it with any compatible carrier I choose?
  • Hello, my phone was unlocked by a friend a while back and everything was fine. Just recently, with the 4.4.3 update when I go to update it goes to the bootloader menu(teamwin?) after the download. Not sure what to push, so I restart the phone and the update doesn't take effect. Nexus 5, please help!
  • Can a phone be rooted while not activated? My Girlfriend purchased a phone and is not currently activated on a wireless provider. She tired to activate her phone with her carrier and they told her, that her phone was locked. Any help would be great!