Question Question about Odin - Samsung Galaxy S21 Ultra

I have a simple question about Samsung Odin software. If Odin can flash stock rom without unlock bootloader; does it mean at least in theory that a custom rom can also be flashed without unlock the bootloader?

No, encryption and digital signatures won't allow it.

Furious Froyo said:
No, encryption and digital signatures won't allow it.
Click to expand...
Click to collapse
This answer another question I posted after that.
I would like to install a custom rom but the idea to unlock the bootloader is something I don't like. I use apps for financial transactions and some of these does not accept to operate with bootloader unlock.

Related

Questions From a Would be Owner

Hello guys,
Just a few questions so I know what I am getting into
1) The phone can be rooted. However, if i want to run on a custom ROM or use mods such as the music mod, I would have to unlock the bootloader, yes?
2) Once the bootloader is unlocked, I would lose the 'Bravia Engine' feature of the phone. What else will I lose? For those who have lost it, is the trade off, of being able to run Custom ROMs and mods while losing the 'Bravia Engine' feature worth it?
3) If I have to send the phone for warranty, I could just re-lock the bootloader and send it back for warranty. Is there a chance somehow that they'll reject the phone if they detected that the phone's bootloader was tempered with?
arvin2212 said:
Hello guys,
Just a few questions so I know what I am getting into
1) The phone can be rooted. However, if i want to run on a custom ROM or use mods such as the music mod, I would have to unlock the bootloader, yes?
Click to expand...
Click to collapse
no
arvin2212 said:
Hello guys,
Just a few questions so I know what I am getting into
2) Once the bootloader is unlocked, I would lose the 'Bravia Engine' feature of the phone. What else will I lose? For those who have lost it, is the trade off, of being able to run Custom ROMs and mods while losing the 'Bravia Engine' feature worth it?
Click to expand...
Click to collapse
No clue since mine isn't/can't be unlocked. The only reason for me to unlock the BL (Even though it can't be done) would be, to flash a custom kernel, beside that I don't see any other reasons why I should unlock it.
arvin2212 said:
Hello guys,
Just a few questions so I know what I am getting into
3) If I have to send the phone for warranty, I could just re-lock the bootloader and send it back for warranty. Is there a chance somehow that they'll reject the phone if they detected that the phone's bootloader was tempered with?
Click to expand...
Click to collapse
Once it's unlocked there is no way back.
So if you want to root your phone, use custom roms (without custom kernels) you don't need to unlock the bootloader.
Dsteppa said:
no
No clue since mine isn't/can't be unlocked. The only reason for me to unlock the BL (Even though it can't be done) would be, to flash a custom kernel, beside that I don't see any other reasons why I should unlock it.
Once it's unlocked there is no way back.
So if you want to root your phone, use custom roms (without custom kernels) you don't need to unlock the bootloader.
Click to expand...
Click to collapse
Thank you very much for the reply.
I assumed as such from reading some posts initially, but then I went to the ROM section (If i am not mistaken) and there is a post on how to unlock the bootloader and then there is the Why section where it says that you could then use custom ROMs and mods which then confused me.
If i can use custom roms and mods without unlocking the bootloader, then I'll definitely be getting this phone.
I'll take advantage of this thread to ask one simple question: once we rooted the XZ and flash the Mods we find useful, we no longer get updates from the official Sony firmware in the future, right?
labroste said:
I'll take advantage of this thread to ask one simple question: once we rooted the XZ and flash the Mods we find useful, we no longer get updates from the official Sony firmware in the future, right?
Click to expand...
Click to collapse
First backup your firmware with http://forum.xda-developers.com/showthread.php?t=2188129
You can go back at any time to your original firmware and you can have the updates via pcc or sus.
Sent from my C6602 using xda premium

Relock after Root?

Hello Guys
Do you relock the bootloader after root of nexus 6?
It's probably not the best idea. Though now the "OEM unlocking" option seems to stick after a reboot on 5.1+ it's probably not as risky as it was.
Oniska said:
Hello Guys
Do you relock the bootloader after root of nexus 6?
Click to expand...
Click to collapse
I'm going to go ahead and just say no. No reason to relock other than RMA or resale. Best to leave unlocked just because if you run into issues, it's much easier to recover if your bootloader is unlocked.
Never relock unless you are on a stock image
I have never relocked a bootloader, ever.
Old thread I realize, but wouldn't this be useful to keep the anti-theft feature intact while rooted? And furthermore, does it actually work? I.e. does it leave root intact after it's locked but forbid flashing new roms to circumvent anti-theft. (I own a Nexus 6P by the way, but imagine the regular 6 has an updated bootloader with the same features.)
Rakeesh_j said:
Old thread I realize, but wouldn't this be useful to keep the anti-theft feature intact while rooted? And furthermore, does it actually work? I.e. does it leave root intact after it's locked but forbid flashing new roms to circumvent anti-theft. (I own a Nexus 6P by the way, but imagine the regular 6 has an updated bootloader with the same features.)
Click to expand...
Click to collapse
the problem is if your bootloader is locked, and you ho into a bootloop for amy reason, and your oem unlock option is not enabled in the developer options, then you bricked your phone. most people that lock their bootloaders, or have them locked, dont enable the oem unlick option. if thats not enabled, and youre in a bootloop, you cant flash a factory image or do anything else to fix it.
Rakeesh_j said:
Old thread I realize, but wouldn't this be useful to keep the anti-theft feature intact while rooted? And furthermore, does it actually work? I.e. does it leave root intact after it's locked but forbid flashing new roms to circumvent anti-theft. (I own a Nexus 6P by the way, but imagine the regular 6 has an updated bootloader with the same features.)
Click to expand...
Click to collapse
If you are encrypted, the only thing a locked bootloader adds is the ability to flash a custom boot.img that can decrypt your data (which doesn't exist). It's a very hypothetical scenario. The problems with locking the bootloader are as mentioned above by @simms22

How to relock the bootloader?

Hi,
I've searched and found how to do it but it was for Android 5.1 but I'm on 7.0 and I my recovery is TWRP 3.0.2-0 and apparently there are more steps to do if you are on TWRP, I'm wondering what are they.
Thanks
test84 said:
Hi,
I've searched and found how to do it but it was for Android 5.1 but I'm on 7.0 and I my recovery is TWRP 3.0.2-0 and apparently there are more steps to do if you are on TWRP, I'm wondering what are they.
Thanks
Click to expand...
Click to collapse
First, questions need to go in the Nexus 6 Q&A, Help & Troubleshooting Thread, not the General thread. Second, the steps to lock the bootloader have not changed. It's done from the bootloader with fastboot and the command "fastboot oem lock". It shouldn't matter what recovery you have.
Re-locking needs stock recovery(maybe full stock; boot, recovery, system) if you try to re-lock your boot loader without stock recovery you might hardbrick your phone. So just backup your apps and files, flash a stock image from google and re-lock your boot loader with "fastboot oem lock". Which probably needs wiping your phone.
Before you do anything search these forums for the many people who locked their bootloader and then when they had problems ended up with a bricked and useless device. Unless you have a very special reason for locking, leave it unlocked
dahawthorne said:
Before you do anything search these forums for the many people who locked their bootloader and then when they had problems ended up with a bricked and useless device. Unless you have a very special reason for locking, leave it unlocked
Click to expand...
Click to collapse
this right here...there is really no reason to ever re lock your bootloader
I flashed the factory image and and it went fine. But the bootloader is still unlocked. My main concern for locking the bootloader is to prevent any malicious app to root the phone and hide themselves by like installing as system app or something. And I'm not planning to flash any custom ROM. So:
1- Since I'm on stock ROM, is there still a possibility of hard bricking my phone if I relock?
2- If I leave it unlocked, will malwares be able to tamper with the phone by the means I mentioned or similar approaches?
Thanks
2. No, they don't. Bootloader is on a completly different layer.
test84 said:
I flashed the factory image and and it went fine. But the bootloader is still unlocked. My main concern for locking the bootloader is to prevent any malicious app to root the phone and hide themselves by like installing as system app or something. And I'm not planning to flash any custom ROM. So:
1- Since I'm on stock ROM, is there still a possibility of hard bricking my phone if I relock?
2- If I leave it unlocked, will malwares be able to tamper with the phone by the means I mentioned or similar approaches?
Thanks
Click to expand...
Click to collapse
I feel your concerns. I think the safest bet is to watch where you download apps and content from. And make sure "unknown sources" is turned off. That should minimize your potential for problems. I think the main thing is watching where you get apps from.

[Q] No OEM Unlock, Rooting, and stock ROM

I know that there are a lot of the missing OEM Unlock posts, but this isn't about how to force it to appear.
What I would like to know is that if I want to stay on the stock ROM, but I don't have the OEM unlocked option, would I be able to factory reset to clear out encryption and then root with Magisk?
The guide says that I need to have OEM unlocked to be able to root, so I'm curious what would happen if I tried to root with the OEM still being locked? Would I soft brick it?
This is quite different from the other phones I've used and it's extremely frustrating that Samsung decided to pull this kind of bs on everyone and so far, there's no solution to it.
Thanks
If the OEM switch is not visible and switched on, then you cannot flash any non-official binaries, which means you can't flash TWRP or Magisk, which at this point means you can't get root. That's why everything boils down to the OEM switch being enabled. Please contact Samsung expressing your dissatisfaction about this OEM issue. All of us should, until they react to remedy this.
If we can get to fastboot, why can't we boot TWRP, install Supersu/magisk and dm-verity thus gaining root.
This wouldn't replace the stock recovery.
I believe this was how the Axon 7 was rooted prior to bootloader unlock being presented/found.
I do this on one of my phones (not Samsung) as I only want root access and still be able to get OTA updates.
Would booting TWRP instead of flashing it trip Knox and would root be gained or would you find the boot partition or other system files be altered and you get the error that seems to popping up on these devices?
Just throwing this out there as food for thought.
ultramag69 said:
If we can get to fastboot, why can't we boot TWRP, install Supersu/magisk and dm-verity thus gaining root.
This wouldn't replace the stock recovery.
I believe this was how the Axon 7 was rooted prior to bootloader unlock being presented/found.
I do this on one of my phones (not Samsung) as I only want root access and still be able to get OTA updates.
Would booting TWRP instead of flashing it trip Knox and would root be gained or would you find the boot partition or other system files be altered and you get the error that seems to popping up on these devices?
Just throwing this out there as food for thought.
Click to expand...
Click to collapse
Having an unlocked bootloader is what would allow us to use fastboot to boot or flash an image. Just because we can access fastboot, doesn't mean we can get it to write to partitions, even temporarily. I haven't messed with a Samsung phone for years, so I could be wrong. This has been my experience with google bootloader in general.
fragtion said:
If the OEM switch is not visible and switched on, then you cannot flash any non-official binaries, which means you can't flash TWRP or Magisk, which at this point means you can't get root. That's why everything boils down to the OEM switch being enabled. Please contact Samsung expressing your dissatisfaction about this OEM issue. All of us should, until they react to remedy this.
Click to expand...
Click to collapse
From what I did read from other threads, if you don't see the option in the Developer Option Settings, then you shouldn't need to enable it
77Eric77 said:
From what I did read from other threads, if you don't see the option in the Developer Option Settings, then you shouldn't need to enable it
Click to expand...
Click to collapse
I was reading about this as well and what I got from that was in regards to custom roms, the oem unlock option is default to unlock and hidden. but for the stock rom, it's locked by default unless visibly given the option. otherwise when you go into download mode, it'll show FRP Lock: On.
Sent from my SM-G930F using Tapatalk
di11igaf said:
Having an unlocked bootloader is what would allow us to use fastboot to boot or flash an image. Just because we can access fastboot, doesn't mean we can get it to write to partitions, even temporarily. I haven't messed with a Samsung phone for years, so I could be wrong. This has been my experience with google bootloader in general.
Click to expand...
Click to collapse
Ah, but if I want to just root and nothing else, would I still need to have the bootloader unlocked? I'm used to rooting stuff but the technicalities and mechanics of the process escapes mr.
my hope is to atleast root the stock rom and factory reset including wiping the internal sd to start fresh. but if I factory reset on a stock rom, the internal storage would still be encrypted right?
Sent from my SM-G930F using Tapatalk
mputtr said:
Ah, but if I want to just root and nothing else, would I still need to have the bootloader unlocked? I'm used to rooting stuff but the technicalities and mechanics of the process escapes mr.
my hope is to atleast root the stock rom and factory reset including wiping the internal sd to start fresh. but if I factory reset on a stock rom, the internal storage would still be encrypted right?
Sent from my SM-G930F using Tapatalk
Click to expand...
Click to collapse
This is why I want to know if we can boot TWRP. It boots TWRP but leaves the stock recovery.
However, I'm not sure if the boot image is altered when flashing root. I know Magisk seems to alter the boot image but not sure if SuperSU does.
Would this trigger KNOX?
If it does trip KNOX, it's not worth booting into TWRP, might as well just bite the bullet and install but only if bootloader is unlocked 1st... Too expensive to just brick it for an experiment...
ultramag69 said:
This is why I want to know if we can boot TWRP. It boots TWRP but leaves the stock recovery.
However, I'm not sure if the boot image is altered when flashing root. I know Magisk seems to alter the boot image but not sure if SuperSU does.
Would this trigger KNOX?
If it does trip KNOX, it's not worth booting into TWRP, might as well just bite the bullet and install but only if bootloader is unlocked 1st... Too expensive to just brick it for an experiment...
Click to expand...
Click to collapse
personally I don't care about knox. I just want to be able to root and restore my apps so I can transfer my stuff from my s7 to the note 8 and freeze all the bloatware like touchwiz and stuff.
from what I gleaned from reading the threads is magisk makes a copy of the boot image as a backup.
but again I just want root and I can wait for a longer term solution in how to fix this moronic 7 day jail bs.
but I think knox will get tripped the moment you root
Sent from my SM-G930F using Tapatalk
mputtr said:
I was reading about this as well and what I got from that was in regards to custom roms, the oem unlock option is default to unlock and hidden. but for the stock rom, it's locked by default unless visibly given the option. otherwise when you go into download mode, it'll show FRP Lock: On.
Sent from my SM-G930F using Tapatalk
Click to expand...
Click to collapse
I didn't have OEM option as well (FRP lock was ON), I just followed me2151 guide but I was getting the partition error, so in first part I also added BL and after that everything went smoothly.
KNOX wasn't tripped, it's rooted as of this moment and tomorrow I will be installing custom rom.
PS: And yes it was an experiment but I was willing to take the risk because after reading half a day about no OEM option in developer options everyone was saying if it's not there you don't need it, I wasn't 100% sure but I was 98% sure I'm not going to brick it. btw I'm using Telus N950W note8 (locked)
I think you might want to be careful on that. I'm not sure who "everyone" is but the others like Dr.Ketan did not even recommend rooting without unlocking the option first and it seems to me that the general gist of the other thread (the 150+ page thread) was that you need it explicitly unlocked.
The ones who talked about not seeing the option means you probably don't need it are talking about custom roms (like renovate) that purposefully hid the option since it's already defaulted to unlocked on that rom.
I haven't used any custom roms yet, but that seems to be what I'm reading.
77Eric77 said:
I didn't have OEM option as well (FRP lock was ON), I just followed me2151 guide but I was getting the partition error, so in first part I also added BL and after that everything went smoothly.
KNOX wasn't tripped, it's rooted as of this moment and tomorrow I will be installing custom rom.
PS: And yes it was an experiment but I was willing to take the risk because after reading half a day about no OEM option in developer options everyone was saying if it's not there you don't need it, I wasn't 100% sure but I was 98% sure I'm not going to brick it. btw I'm using Telus N950W note8 (locked)
Click to expand...
Click to collapse
just following up. Were you able to root and flash a custom rom with OEM Unlocked checked after all?
Sent from my SM-G930F using Tapatalk
mputtr said:
just following up. Were you able to root and flash a custom rom with OEM Unlocked checked after all?
Sent from my SM-G930F using Tapatalk
Click to expand...
Click to collapse
I was able to root it but the boot loader is still locked. It's faster without the bloatware and what not. KNOX is disabled. There is still no twrp and custom rom for Snapdragon to the best of my knowledge. It did change the model of the phone from N950W to N950U1.
finally got the OEM Unlock option and rooted + stock recovery... i had to restart my phone to bring my android ID back to the one I always used.. and got locked out...
so 7 more days for me. And all I wanted to do was to have Titanium backup up and running so i can transfer my phone over....
i am hating what samsung has done

Flashing firmware query

Is it mandatory to unlock bootloader in order to say flash a EU firmware on a China firmware phone? I ask only because I've read a few guides in order to install custom roms which obviously need a bootloader unlock, but wondering like I said if it's required to just flash a different firmware, thanks in advance.
Yes, you must open your bootloader and keep it unlocked.
Angelina7 said:
Yes, you must open your bootloader and keep it unlocked.
Click to expand...
Click to collapse
Urgh I was hoping I could avoid that but it is what it is

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