Database Develop

[Q] Bootloader and Rooting - which one does what?

Hello,
I just got my new Xperia Z having used my ancient Iphone 1G for the last 4 years and I have no experience with Android and anything related to it what so ever. I've spent the last 2 days tirelessly working my way through various forums, guides, wikis to get an idea what I'm dealing with here and where to start, but there's an important decision that I could really use your thoughts and tips on.
After reading up on it, I decided I want to root my phone and this seems to be somehow connected to unlocking the bootloader and this is where I'm worried. I read the guide on how to unlock the bootloader and the warning about losing DRM Keys and the consequences of this scared me away from it. Now I'm left wondering, and this is my actual question here:
What is the difference between unlocking the bootloader and rooting my phone and simply rooting without unlocking the bootloader?
And in case the things I want to do are only available with an unlocked bootloader: how damaging is it to lose DRM keys and therefore the bravia engine and gracenote? What made you decided for or against unlocking the bootloader?
Thanks!

Hi,
maybe I can help you.
Bootloader is like the BIOS of a PC. It checks everything at start up.
Locked Bootloader only allows to run the Stock FW and in this case the DRM-Keys are working (everything is checked and safe)
Unlock the Bootloader means you were able to install an modified / other FW and then you loose the DRM-Keys (the manufacturer hasn´t checked the FW and it is in the eyes of an manufacturer "not safe". You will also loose your warranty.
If you unlock the bootloader Root is always possible as I know.
In this case the system is not from the manufacturer and unofficial modification could be done to the system. Normally all modified Systems have Root access. So you were able to do things that the manufacturer has normally not allowed. Modify system files or something like that. Also it could be possible to copy for example a downloaded and payed movie to another device. This is why you were not able to download a movie on the Play Store if you have root. On a locked bootloader the FW (system) does not give you the possibility to copy the movie to an other device and everything is "safe" (from the view of companies). No illegal copies are possible. (DRM-Keys)
Since some days Root is also possible on a locked bootloader.
The bootloader is checking the status (locked) .. then checking the FW (stock) ... DRM-Keys still valid.
But due to the root access you were also able to modify system files and apps can recognize that you have root access. So you can still use the bravia engine for example (DRM-Keys are ok). But the Google Play Store will still recognize that you have root and will not let you download movies.
This is my experience with Root ... If something is not correct, please correct me

UserX10 said:
Hi,
maybe I can help you.
Bootloader is like the BIOS of a PC. It checks everything at start up.
Locked Bootloader only allows to run the Stock FW and in this case the DRM-Keys are working (everything is checked and safe)
Unlock the Bootloader means you were able to install an modified / other FW and then you loose the DRM-Keys (the manufacturer hasn´t checked the FW and it is in the eyes of an manufacturer "not safe". You will also loose your warranty.
If you unlock the bootloader Root is always possible as I know.
In this case the system is not from the manufacturer and unofficial modification could be done to the system. Normally all modified Systems have Root access. So you were able to do things that the manufacturer has normally not allowed. Modify system files or something like that. Also it could be possible to copy for example a downloaded and payed movie to another device. This is why you were not able to download a movie on the Play Store if you have root. On a locked bootloader the FW (system) does not give you the possibility to copy the movie to an other device and everything is "safe" (from the view of companies). No illegal copies are possible. (DRM-Keys)
Since some days Root is also possible on a locked bootloader.
The bootloader is checking the status (locked) .. then checking the FW (stock) ... DRM-Keys still valid.
But due to the root access you were also able to modify system files and apps can recognize that you have root access. So you can still use the bravia engine for example (DRM-Keys are ok). But the Google Play Store will still recognize that you have root and will not let you download movies.
This is my experience with Root ... If something is not correct, please correct me
Click to expand...
Click to collapse
Hi and thanks a lot for your reply, helped me understand the difference of both better!
If I only root but do not unlock my bootloader will I be able to do anything other than using custom firmware (ROMs)? Will I be able to install Apps that require root or install custom modification like the ones offered on this forum that need to be "flashed in recovery" if I only root not unlock my bootloader?
Also, still looking for some pros and cons (my second question in the original post).
Appreciate all your help!

root will give you access to recovery (in time - still in development) and you can install apps that require root access
custom mods - yes you can install them via recovery and some can be installed with root access and without recovery
if u unlock bootloader you will lose bravia engine not sure bout gracenote as i dont use it
you can check this thread http://forum.xda-developers.com/showthread.php?t=2154310 too see what have people wrote bout
rooting with unlocked bootloader

The main thing pointing me towards unlocking bootloader (I'm already rooted on locked bootloader) is being able to install kernels and major roms.
For example, you could flash Doomlords kernel and over clock the processor a bit, but you could also reduce power and save battery
The major roms I speak of are the ones that are kinda cross device: CyanogenMod and Paranoid Android to name 2. CM is based on pure android, no Sony changes so we can't flash that on locked bootloaders as it requires changing kernel. PA is same.
As for the downsides. I'm not too bothered about DRM keys. I use Spotify for music so don't think I need gracenote. Never watched a movie on my phone. BE2 isn't my cup of tea... Over saturates everything.
I'm going to look into DRM keys more tomorrow, but if someone can correct anything I've written then please do
Not being able to restore via Sony tools... Isn't that bad as you're going to be using flash tool a lot so you'll be used to that. Just keep a generic stick firmware .ftf around in case something goes horrendously wrong (usually recovery backup is enough I think).
Sent from my C6603 using Tapatalk 2

Nice thread, I had this question too
It's my first android and I guess I should unlock the bootloader and then root, this way I won't have to wipe my data later when I decide to try cyanogenmod or something else?
Also what happens if sony release 4.2? Will I lose my bootloader unlock and root?

Al Gore said:
Nice thread, I had this question too
It's my first android and I guess I should unlock the bootloader and then root, this way I won't have to wipe my data later when I decide to try cyanogenmod or something else?
Also what happens if sony release 4.2? Will I lose my bootloader unlock and root?
Click to expand...
Click to collapse
I would say root without unlock for now.
When you want to try cyanogenmod or others. Just backup everything using titanium backup and then u can restore after unlocking.
Rooting with a locked bootloader means sony are not aware your bootloader is unlocked
Sent from my C6603 using xda premium

Thanks for all your replies, helped me out a ton!
I think Im gonna root without unlocking bootloader for now to get my feet wet and get a grasp of it's capabilities and limits. Can always restore the phone if I screw up and can always unlock bootloader later if I need it.

Al Gore said:
Nice thread, I had this question too
It's my first android and I guess I should unlock the bootloader and then root, this way I won't have to wipe my data later when I decide to try cyanogenmod or something else?
Also what happens if sony release 4.2? Will I lose my bootloader unlock and root?
Click to expand...
Click to collapse
If you unlock Bootloader, you shouldn't update from Sony. Since you've (hypothetically) already unlocked, you already have 4.2 avaliable from FXP and if you really want the Sony Update maybe you could flash it via flash tool. Bootloader unlock will never be lost (until someone can create an explicit relock file, but customs roms won't relock it). Root maybe lost if you flash a rom without it but you should be able to get it back easy.
With locked bootloader, we have to wait for Sony to bring 4.2 as we can't access the kernel, but we retain the ability to use the official updates. If we're rooted and we update, we are no longer rooted and we may be unable to use the same exploit.
Sent from my C6603 using Tapatalk 2

UNLOCKING BOOTLOADER : What i'm going to lose.

Guys, i've been using many mainstream brands like HTC, Sony, Samsung, etc but im newb to Huawei.
For Sony device, im going to lose DRM keys for good after unlocking BL (not to mention backup TA) and many other features & functions like screen mirroring & camera quality degrade.
For Samsung, the well known Knox.
Im about to unlock my P9Plus but by reading this, quoted frm Huawei bootloader unlocking page, im abit scared of losing Leica image processing for instance.
4．Some functions will no longer work after you unlock the bootloader. For example, you will no longer be able to use Digital Rights Management (DRM) keys and digital content that you have purchased. Upgrading software using Firmware Over-The-Air (FOTA) or a microSD card may fail or your device may not function properly after upgrading.
Click to expand...
Click to collapse
Can anyone shed some lights?

I asked this before i unlocked my bootloader, as my previous phone was also a Sony.
I was told nothing would be lost, and from what i can tell, the phone still seems the same as it was out of box.
If you do notice anything, please let me know as well.
I haven't received any OTA update, but i can always download and update via SD-Card if i require.
Haven't tried playing any videos on the phone, besides ones that I've taken myself, but nothing i have contains DRM protection so I don't see any issues there anyway.

This is my 3rd Huawei Device after the P8 & Mate 8.
On all the devices I didn't notice any changes after unlocking.

how about screen mirroring & netflix/iflix HD. if im not mistaken netflix wont play HD movies if DRM is absent on device.

Hi, i wan't to temporary unlock BL only to de-brand my P9+. So i'll relock it after the operations. In that scenario, what happens to my warranty? If now I check the warranty status with Huawei services, i receive a message that the phone i regularly under warrenty until xx/xx/xxxx. If i unlock BL that message remains or will change in something as "NO WARRANTY..."
Thanks

stalvatero said:
Hi, i wan't to temporary unlock BL only to de-brand my P9+. So i'll relock it after the operations. In that scenario, what happens to my warranty? If now I check the warranty status with Huawei services, i receive a message that the phone i regularly under warrenty until xx/xx/xxxx. If i unlock BL that message remains or will change in something as "NO WARRANTY..."
Thanks
Click to expand...
Click to collapse
If you somehow already have the bootloader unlock code (e.g. from DCUnlocker), then the warranty displayed on the website will not void, at least on my Singapore's VIE-L29C636. But I am not sure through if you get the unlock code via the official EMUI website. Your bootloader's state will become "unlocked", and if you do relock your bootloader, it will show "relocked" instead of "locked". Read my post here to revert it back to "locked" state.

everybody MIA :laugh:
Sent from my Huawei P9 Plus using XDA Labs

Bootloader re-locked after OTA update

Hey, for a reasons I needed to do ota update (reflashed stock recovery[extracted from matching update] before doing so), now when im trying to reinstall TWRP i've noticed that my bootloader re-locked on its own.
Was this supposed to happen? iirc people keep telling you that you can't relock bootloader without it's backup from locked state.
It's quite annoying that it happen since I did pay for unlock via DC unlocker and now huawei stopped distributing unlock codes so I'll probably need to pay DC again.
Cheers!
edit: DC unlocker did not even allow me to Unlock bootloader, only thing i saw was Lock bootloader, but there was option to "Read bootloader code" (no credits needed) and I managed to unlock bootloader again using fastboot and this code

TheRadziu said:
Hey, for a reasons I needed to do ota update (reflashed stock recovery[extracted from matching update] before doing so), now when im trying to reinstall TWRP i've noticed that my bootloader re-locked on its own.
Was this supposed to happen? iirc people keep telling you that you can't relock bootloader without it's backup from locked state.
It's quite annoying that it happen since I did pay for unlock via DC unlocker and now huawei stopped distributing unlock codes so I'll probably need to pay DC again.
Cheers!
edit: DC unlocker did not even allow me to Unlock bootloader, only thing i saw was Lock bootloader, but there was option to "Read bootloader code" (no credits needed) and I managed to unlock bootloader again using fastboot and this code
Click to expand...
Click to collapse
This is a flag in OTA update, it may be present or not (now seems to be always enforced, new Huawei policy) that OTA locks Bootloader
You cannot disable this flag in OTA package
Bootloader is not relocked but really locked (better for those who go to service under warranty)
Bootloader code is unique for your device.
No matter did you obtain it from Huawei or DC, you have TO KEEP it, you don't need to pay, read or ask again, just use the same bootloader code for the same phone for the lifetime of your phone

zgfg said:
This is a flag in OTA update, it may be present or not (now seems to be always enforced, new Huawei policy) that OTA locks Bootloader
You cannot disable this flag in OTA package
Bootloader is not relocked but really locked (better for those who go to service under warranty)
Bootloader code is unique for your device.
No matter did you obtain it from Huawei or DC, you have TO KEEP it, you don't need to pay, read or ask again, just use the same bootloader code for the same phone for the lifetime of your phone
Click to expand...
Click to collapse
thanks for the answer, didnt know about flag nor that bootloader unlock code can be used multiple times(and that its paired with HW)
nevertheless, as I said in my edit I managed to get my unlock code for free with dc unlocker

TheRadziu said:
thanks for the answer, didnt know about flag nor that bootloader unlock code can be used multiple times(and that its paired with HW)
nevertheless, as I said in my edit I managed to get my unlock code for free with dc unlocker
Click to expand...
Click to collapse
Did you compare it, is it the same like previous time

zgfg said:
Did you compare it, is it the same like previous time
Click to expand...
Click to collapse
that's what I suspect, but sadly can't confirm or deny. I think I didn't even see the code itself when I used it for the first time due to the fact that unlock process was automatized within DC unlocker's client app, so all I had to do was to prepare the phone and press Unlock Bootloader within the client

TheRadziu said:
that's what I suspect, but sadly can't confirm or deny. I think I didn't even see the code itself when I used it for the first time due to the fact that unlock process was automatized within DC unlocker's client app, so all I had to do was to prepare the phone and press Unlock Bootloader within the client
Click to expand...
Click to collapse
I used DC client once (4 Euros), I obtained the code (saved it for future) and used in Fastboot to unlock Bootloader just like previously for the other Huawei phone whose code I obtained for free from Huawei (before they closed this service)

Retrieve Bootloader Unlock Code from a rooted phone?

Hi,
I have an bootloader-unlocked P10, that I unlocked a long time ago. But I didn't save the unlock code. Is there any way to retrieve the code from a rooted phone? Using TWRP?
Bonus question - what actions will cause my phone to be accidentally re-locked? How to avoid this in case I can't get my code again?

It's not possible to get the unlock code without Huawei, even with a rooted phone.
Since Huawei won't send you the code anymore, the only way to get the code is DC Phoenix (it costs around US$ 4, I think).
A re-lock can caused by many factors:
Failed firmware installation
Failed update
Failed root / unroot
Failed factory reset
Corrupt file partition
Factory reset with disabled "OEM Unlock" option in settings
If you just update the phone via OTA or methods like my script the bootloader should stay unlocked. But there's no real warranty, every device is different and even if you did everything right the software can mess something up.
A re-lock mostly causes a factory reset.
So, if you want to be safe, get your unlock code with DC Phoenix (I never used this tool) and write your code down for the future.
DC Phoenix should also work if your phone is bricked.

Need to relock bootloader - make firmware look new to retailer

I need to send in my Xperia 10 dual sim for repair (probably need new battery), it's still on warranty.
Now I had lineageOS on it, and hoped to resolve the battery charging problems by re-flashing the original firmware. I don't have a Winodws computer, so I used XperiFirm and Newflasher on Linux to do that. Everything looks original now, But of course I still have the "your device can't be checked for corruption" effin message popping up, and I don't know if the retailer will service my phone for free if they can see I had the bootloader unlocked.
Now I read that re-locking the bootlaoder will
1) also reset the whole thing to factory settings, delete all data.
2) break the camera?
1.) Is not a problem, they want you to do that before service anyways, and I backed everything up.
2.) Is a problem, because they might yet deduce that I unlocked the bootloader, or give me some other trouble.
However I also saw it hinted in this forum that re-locking the bootloader should be fine if it is done on the original firmware, which would be the case.
...=> If I re -lock, do you think I'll be safe sending it back, regarding signs of the BL being previously unlocked?