Is your Android phone's bootloader unlocked? Is it SIM unlocked? What's the difference?
There's been a bit of confusion in the blogs the past few days over unlocking phones. Maybe you're wondering about an unlocked bootloader. Or maybe you need something that's SIM unlocked. Or maybe you want to unlock your phone's bootloader, but you can't, because it's encrypted.
It's confusing, we know. Even bloggers have a hard time keeping it all straight. But you've come to the right place. We don't have that problem here.
So let's have a little refresher course on what we mean when we talk about unlocking things, shall we?
Here in the United States, this is the one you're more likely to be concerned with.
Every Android smartphone has what's called a "bootloader." Think of it as a set of instructions that runs before the Android operating system kicks in. No bootloader, no phone.
Now, 99.99 percent of Android smartphones ship with a "locked" bootloader. (The other .01 percent are phones you probably don't want to know about anyway.) It's "locked" insofar as you can't overwrite it with files that won't work -- or overwrite it with any files for that matter -- either accidentally, or on purpose if you're the tinkering type.
It's also a security measure. You can't unlock a bootloader without erasing all the data that's already on the phone. That means someone can't steal your phone, unlock the bootloader and circumvent your log-in password or anything to get to your data -- it'll be erased in the process! So when you start seeing headlines that say "Such-and-such phone ships with a locked bootloader!", you know not to freak out, because nearly every single Android phone ships with a locked bootloader. And you want it to.
The question is whether you're actually able to unlock the bootloader.
But let's back up for a second. Why on god's green Earth would you want to mess around with a bootloader?
The simple answer is so you can tinker. So you can flash new kernels. Or ROMs. Or even just a custom recovery. The bootloader is the gatekeeper for all this stuff. Again, it's locked out of the box so that you can't accidentally break something, or so that someone (or something) can't purposefully break things.
The act of encrypting a bootloader means that it can't be unlocked without a key. No key, no unlocked bootloader, and no hackery. That's what folks are upset about. They want to tinker, and whomever decided an encrypted bootloader is the way to go -- and it really doesn't matter if it was the carrier or the manufacturer -- isn't making it easy. There are arguments on both sides. Locking down the phone so it can't be tinkered with means fewer customer-service calls, which cost companies money. On the other hand, you bought the phone, you should damn well be able to do whatever you want with it. We get that, too.
Not every phone throws the wall of encryption at you. Google's Nexus line of devices can be unlocked after about 30 seconds and a three little words in a command line: fastboot oem unlock. Many new HTC phones are easily unlocked with a tool provided by HTC. Sony has its own method. It requires a little more time and brain power, but it's not all that hard to do.
So that's bootloader unlocking -- opening up a way to more easily tinker with your phone.
The other kind of "unlocking" is SIM unlocking. If you've been living in the GSM world (ie not on Sprint or Verizon here in the States), chances are you've heard this before.
A brief primer: To use a phone on a GSM network anywhere, it needs a SIM card. That's the little card that lets the network recognize your phone, so that you can make phone calls and get data. (You also can store a little bit of information on it, most often contacts.) GSM phones use SIM cards. In the U.S., that means AT&T and T-Mobile. Now, to use an LTE network -- like what Verizon's had for more than a year now, and Sprint's just getting going -- your phone will need a SIM card as well. That's what's relatively new for Verizon and Sprint, and likely where some of the confusion is creeping in.
Think of it like this: LTE is a GSM standard, therefore it uses a SIM card. Easy enough. Recently, Verizon announced that a couple of its phones -- including the Droid RAZR/MAXX and the Galaxy S III -- would receive software updates so that you could use them outside the United States, on GSM networks. In other words, you update the phone, add international data and calling to your plan, and things should just work.
So back to SIM unlocking. There are two ways to purchase GSM-capable phones -- SIM locked, or SIM unlocked. The difference is simple. With a SIM-unlocked phone, you can take a SIM card from any carrier -- AT&T, T-Mobile, Three, Vodafone, O2, etc. -- pop it in the phone, and it should work after a few changes in your settings. There's nothing else keeping it from working.
A SIM-locked phone blocks the use of other carriers' SIM cards. Take, say, a Vodafone SIM card and put it into an AT&T Galaxy S III, and the phone's going to ask your for an unlock code. If you don't have the code, you're not going to be using another carrier's SIM card. (Getting the code is easy enough. If your account is in good standing, chances are the carrier will give it to you. Or there are services online that can help, for a fee.)
Why use another carrier's SIM card? Simple: It can be much cheaper than adding international roaming features onto your current plan. Because your carrier loses money when you do that, they don't make it all that easy. (But neither is it all that hard.)
This is not rooting
It's worth noting that nowhere have we mentioned the words "root" or "rooting." Unlocking bootloaders and having a SIM-unlocked phone has nothing to do with having root access on your phone. Having an unlocked bootloader can make gaining root access easier, but a locked bootloader isn't necessarily a deal-breaker.
It's something to keep in mind.
The tl;dr version
Wrapping it all up in two handy bullet points:
- Bootloader unlock: Needed for some serious hacking.
- SIM unlock: Needed to use your phone on other GSM networks.
They're not the same thing. At all. One doesn't have anything to do with the other.