Why do some service providers lock their phones from rooting?

kyrax12

Platinum Member
May 21, 2010
2,416
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Like ATT galaxy note 4. What is the reason behind lock bootloader.

If someone bought their phone then they should be able to do whatever they want with it.
 
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paperwastage

Golden Member
May 25, 2010
1,848
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As webdave says, Same reason why they sim lock phones... Control and support(don't have to worry about user deleting /system and bricking phone)

If you want something guaranteed rootable or bootloader unlock, get a nexus or a developer device (for Verizon)
 

dawheat

Diamond Member
Sep 14, 2000
3,132
93
91
Bootloader and Root access are COMPLETELY DIFFERENT THINGS.

True, but they are inseparable today for Samsung phones. AFAIK there are no known exploits to gain root on later versions of KK and Lollipop. The only method known today is to take advantage of an unlocked booloader.

No unlocked bootloader on a current Samsung phone, no root for you. However between the T-mo Note 4 and Verizon dev edition, there should be a version that can work for most everyone.
 

jhu

Lifer
Oct 10, 1999
11,918
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True, but they are inseparable today for Samsung phones. AFAIK there are no known exploits to gain root on later versions of KK and Lollipop. The only method known today is to take advantage of an unlocked booloader.

No unlocked bootloader on a current Samsung phone, no root for you. However between the T-mo Note 4 and Verizon dev edition, there should be a version that can work for most everyone.

No one has found them yet or made those exploits known. They're still two different things. It's much easier to find a root exploit than it is to find a bootloader modifying exploit.
 

Platypus

Lifer
Apr 26, 2001
31,046
321
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Just wanted to offer some corrections here

1) Your bootloader is not "locked" because Samsung have an awful, insecure by default bootloader. The issue is that it is verifying boot image signatures. You can still technically overwrite them, but they will not boot because signature verification will fail. Semantics.. but, that's the actual situation.

2) Devices are locked for many reasons, the most obvious being the massive security hole it would introduce if they weren't.

3) Root and booting unsigned images are two totally different things. You can root your device's stock firmware without having to modify the boot firmware.

4) MOST of Samsung's devices are unprotected, the 'no unlocked bootloader on a current Samsung phone' is patently false. The *only* carriers which restrict this image verification are Verizon and ATT currently, with Sprint doing this to a handful of devices now. T-Mobile is not enforcing image verification in any way, nor are any international devices fromt hem.

5) There are most definitely active roots available for anything < Android 5.0, and it's a matter of time before the 5.x ones become public.
 

paperwastage

Golden Member
May 25, 2010
1,848
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T-Mobile is not enforcing image verification in any way, nor are any international devices fromt hem.

just a note- the Sony Z3 from T-mobile actually has a locked bootloader... it's strange, because Sony is generally open (they have AOSP binaries and unlockable bootloaders for their int'l phones), and T-mobile is generally open as you've said (most devices they have are bootloader unlockable)

no root or bootloader exploit found yet for the T-mobile Sony Z3 kitkat, even though root exploits are available for other Z3 on kitkat
 

Platypus

Lifer
Apr 26, 2001
31,046
321
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just a note- the Sony Z3 from T-mobile actually has a locked bootloader... it's strange, because Sony is generally open (they have AOSP binaries and unlockable bootloaders for their int'l phones), and T-mobile is generally open as you've said (most devices they have are bootloader unlockable)

no root or bootloader exploit found yet for the T-mobile Sony Z3 kitkat, even though root exploits are available for other Z3 on kitkat

Interesting, tmo must have asked sony to prevent unlocks for this model for some reason.
 

jhu

Lifer
Oct 10, 1999
11,918
9
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Interesting, tmo must have asked sony to prevent unlocks for this model for some reason.

None of this makes any sense. Why keep the S5 unlocked but then lock the Z3? It's as if they had a dart board full of phone names, threw a few darts at the dart board, and wherever the darts land, those phones get locked.
 

Platypus

Lifer
Apr 26, 2001
31,046
321
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None of this makes any sense. Why keep the S5 unlocked but then lock the Z3? It's as if they had a dart board full of phone names, threw a few darts at the dart board, and wherever the darts land, those phones get locked.

I have heard of one other sony phone that was unlockable on their network but this is clearly the outlier here, nothing else on their network is non-unlockable or verifying boot image integrity. The mind boggles.