yashsingh1/xdaforums huggingface dataset:
[Samsung Galaxy S21 Guides, News] clipdawg05:
yeah i bought it while i was in the states. moved to europe recently. what does changing the csc do anyway. i see a lot of people changing it either by dialer code or by samkey. the dialer code does nothing for me
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
Changing the CSC enables carrier-specific features
[Samsung Galaxy S21 Guides, News] this.guy.lol:
I've never heard of having to pay a professional to unlock the bootloader. Every phone I've ever owned I've bootloader unlocked myself. Unless Samsung changed how they do their unlocked bootloader regiments. Can you or someone point me to the threads needed to do the bootloader unlock?
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
When Samsung started doing "locked" bootloaders on the S3 or so, there certainly were hacks and exploits to do it on certain models along the way. And T-Mobile and Sprint devices already came unlocked, up until the S6. But US models have never been user-unlockable via OEM Unlock + Odin, the way that international models are.
[Samsung Galaxy S21 Guides, News] this.guy.lol:
So is root not obtainable on the us versions? :(
[Samsung Galaxy S21 Guides, News] DroidHelp101:
Yea it is. Only on V1 bootloader. You can bootloader unlock install TWRP and root
[Samsung Galaxy S21 Guides, News] entropism:
It's a $150 (I believe) fee, there's a team on XDA that sells it.
[Samsung Galaxy S21 Guides, News] this.guy.lol:
For my purchasing how can I tell if I'm on the V1 bootloader prior to my purchasing?
[Samsung Galaxy S21 Guides, News] DroidHelp101:
Look at your baseband number. The 5th number to the left starting from the right.
[Samsung Galaxy S21 Guides, News] entropism:
Don't know. I'd never pay for the service, so I don't care much about it.
[Samsung Galaxy S21 Guides, News] this.guy.lol:
I agree I would never pay for a rooting service I could just do it myself.
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
But you CAN'T do it yourself. Unless you have an inside source at Samsung who can provide you with the engineer bootloader token to flash in Odin, you need to pay someone who DOES have an inside source
[Samsung Galaxy S21 Guides, News] buzzkill616:
Thank you for this I was switching from ATT to VZW and could not figure out how to flash the stock U1. This finally gave me the info I needed about pulling the sim card before booting.
[Samsung Galaxy S21 Guides, News] jhunkab:
Did you go through transition from ATT (unlocked) S21 to TMB firmware? If yes, any observations/learnings? I am looking to make the same switch. Changing the provider and hoping to use e-Sim from t-mobile if/when they bring it to our S21.
[Samsung Galaxy S21 Guides, News] jhunkab:
I was hoping that ATT-->U1-->TMB transition would let us be on TMB's update schedule. Doing dirty flash to get updates is not fun for daily driver.
[Samsung Galaxy S21 Guides, News] Swagata:
I own the g991u at & t version. I am unfortunately using from an Asian country. I was wondering if I could use the u1 unlocked firmware on my device. Do I need to unlock bootloader if I try the u1 firmware from odin? All I want is to remove all the at&t stuff from my phone.
[Samsung Galaxy S21 Guides, News] jhunkab:
I have moved to U1 firmware showing up as TMB/TMB/ATT. I haven't moved to TMB completely. Will revisit second leg of move from U1->TMB, if/when tmobile enables e-sim.

once I updated to U1 - immediately got an update that was released yesterday for U1 (AUE3). I have taken in the update - seems to be all good so far.
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
AT&T USERDATA for bootloader 4 has been added to the OP links - build UF5. If needed, the rest of the files can be obtained via the various firmware download tools, via CCT or CHA. Bootloader 4 U1 firmware is also out already
[Samsung Galaxy S21 Guides, News] mhamade06:
Could you please provide a recommendation for a professional 3rd party business to do the SIM unlock? Thank you!
[Samsung Galaxy S21 Guides, News] draymond1987:
Can I use this USERDATA for August security patch? (ATT)
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
Yes
[Samsung Galaxy S21 Guides, News] draymond1987:
Thanks!! Look, I don't wanna hijack but I have a small question, that'll get a faster answer here. Are S21's perm locked to X carriers?? SIM unlock, not bootloader.
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
If it's a G991U, then yes.

If it's a G991U1 (an original one, not a G991U that's had U1 firmware flashed to it), then no

If you need one SIM unlocked, I can give you a recommendation for an experienced professional business to do the unlock
[Samsung Galaxy S21 Guides, News] draymond1987:
It's a G991U, that I have flashed U1 firmware to, and yes! I would love a service. I actually just put the global (snapdragon) firmware on and "chat features" don't work, and other carrier related things. Maybe an unlock will help?? And I don't have another SIM to insert. Tmobile variant.
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
A SIM unlock isn't going to magically make certain carrier functions work, if they don't already.

A SIM unlock only helps you if the device is actually still SIM locked, and if you're looking to use it with a totally different network than what it's locked to
[Samsung Galaxy S21 Guides, News] draymond1987:
Yes yes, I wanna use it with another carrier, in the near future :D
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
And which carrier would that be?
[Samsung Galaxy S21 Guides, News] draymond1987:
More than likely, AT&T. I would prefer VZW but I'm getting tired of T-Mobile
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
Are you the original owner of the device, or did you buy it used?
[Samsung Galaxy S21 Guides, News] draymond1987:
I bought it off Swappa "new" condition, from a wholeseller, not an average person. They have hundreds of devices sold.
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
Yes, I'm very familiar with Swappa lol.

When you're ready to switch carriers, PM me to get it unlocked. Just make sure you haven't actually switched yet
[Samsung Galaxy S21 Guides, News] draymond1987:
I dunno when I will switch (gotta research / plan it out) BUT I will!

I can't unlock now without a new SIM?
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
I mean, yeah, that is possible. I guess you don't technically have to wait lol
[Samsung Galaxy S21 Guides, News] draymond1987:
Sign me up!! :)
[Samsung Galaxy S21 Guides, News] Mike_j420:
So I have read thru all the comments here on this thread, I am half way competent but I am still half way confused lol. I have the g991u from ATT and I want to use it with straight talk sim. If I flash the U1 variant will that allow me to use a straight talk sim? would be epic if I could get rid of the annoying Network Unlock Code screen that pops up when I put in a straight talk sim. thanks in advanced.
[Samsung Galaxy S21 Guides, News] Xodium:
No, you have to get it unlocked for it to be SIM unlocked. Flashing different firmware won’t unlock it. Once you’re SIM unlocked though you can flash the U1 firmware and you SHOULD be good to go. Assuming you don’t run into the locked CSC problems that the T-Mobile users are facing.
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
You can use a Straight Talk SIM that runs on AT&T towers without the phone needing to be unlocked.

If you need to use either a T-Mobile or Verizon SIM (due to them having better coverage in your area or whatever the case may be), then the device HAS to be SIM unlocked in order to be used - there's no way around that.

I can provide a recommendation for a professional third party business to do the SIM unlock, if you need/want
[Samsung Galaxy S21 Guides, News] dovid:
Hi - could you DM me the name of those who can get me the token? Thank you!
[Samsung Galaxy S21 Guides, News] var407:
I have flashed the most recent XAA firmware. Patched ODIN will not allow me to flash older versions of the ATT U builds and USERDATA. Can you upload either the current ATT USERDATA or full build?

Thanks.
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
Bootloader 4 ATT USERDATA was uploaded 3 months ago. The rest of the U files can be found all over the internet quite easily if needed
[Samsung Galaxy S21 Guides, News] mido67:
Hello. Is there a tip to enable all 5G bands available on US version to work in Europe? I need n1, n28a & n78...
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
Doesn't look like any of those bands are present on the US version, according to the specs
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
ATT USERDATA has been added for Android 12 - build UK7. All other carriers got this same version so the rest of the files are readily available elsewhere if needed
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
Android 12 is now available for U1, via Frija and the other similar firmware download tools
[Samsung Galaxy S21 Guides, News] 244390341@qq.com:
Hi,bro Can you tell me the third party company?
[Samsung Galaxy S21 Guides, News] ctep:
Do you know if this problem has been solved with latest update on One UI 4.0? I read online that now the phone flashes/restarts to whatever sim card is inserted into the phone.

I'm in the same situation. Would like to use a Straight Talk (backend using Verizon) in the future, but i'm not sure if it'll work properly (with features like wifi calling; voicemail etc) since I have a sim unlocked T-Mobile S21. I don't have a Straight Talk plan to verify this with but, I inserted a Xfinity Mobile (Verizon backend) sim card into it and it restarted and the loading screen was showing Xfinity Mobile instead of T-Mobile; and the service worked fine.

Edit: Did some research found some new info. I don't believe Straight Talk has there own CSC code, so I chose to find a 991U1 version and flashed it. Android 12's versions are hard to come by at this moment because Samsung stopped distributing them for the time being, and I had Android 12 because T-Mobile was faster to push the update than the unlocked versions this time. It was flashed with the latest patched Odin (Odin3 v3.14.1), using CSC file (not HOME_CSC because I didn't care if it wiped the phone). Phone turned on and Model now reads SM-G991U1 but "Service Provider Information" still shows the TMB (T-Mobile version). My main question now is what update path is this on (T-Mobile or the Unlocked)? Strangely I was able to get my hands on a Verizon sim after the flash but it didn't restart when inserting the sim (nor did the bootscreen change to Verizon).

Resources: https://doc.samsungmobile.com/SM-G991U1/TMB/doc.html
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
1. Straight Talk has their own U1 firmware, under CSC "TFN"

2. If you have U1 firmware, you're on U1 update path
[Samsung Galaxy S21 Guides, News] DeathStolas:
I have some questions, if someone could be so kind to answer.

S21

SM-G991U1

Active CSC Code - FKR (im on visible)

Bootloader, PDA, Baseband- G991U1UES4AUJ7

When I use Frija with CSC FKR or XAA android 11 is latest update. But If I check with VZW android 12 is the latest.

Is the U1 firmware not updated yet (please forgive me, I havent been on android in a long time).

Would I lose anything flashing VZW U firmware via download with frija and flash with odin?

Thanks in advance.
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
1. Yes, U1 got its Android 12 update about 6 weeks ago. It appears that it just doesn't exist for your CSC yet

2. You can flash any CSC of U1 Android 12 and you'll be just fine
[Samsung Galaxy S21 Guides, News] Vazovski2007:
U1 android 12 firmware is buggy, I recomend to install U Firmware, For example TMB, Because in U1, VoLTE menu is missing, If you don't care about VoLTE than just go ahead with firmware for xaa
[Samsung Galaxy S21 Guides, News] DeathStolas:
Any reason you would suggest TMB over VZW?

Do i need to flash the user data, or can i forget that to prevent more useless bloat.

Thanks again.
[Samsung Galaxy S21 Guides, News] Vazovski2007:
No it's just from my opinion.

No do not flash user data or you will have career bloatware. Just flash everything do not flash home csc and do not flash user data, Use just normal csc and all other 3 Files, I only can share my experience, in this way everything is working smooth in my case so i Only can suggest this
[Samsung Galaxy S21 Guides, News] DeathStolas:
Awesome thanks!
[Samsung Galaxy S21 Guides, News] DeathStolas:
Does RCS exist in the stock messaging app on any build? Thanks!
[Samsung Galaxy S21 Guides, News] DeathStolas:
I flashed the Tmobile files. When I try to flash back to XAA I get a failed prompt.

On the device this is displayed.

SW Rev check fail : [ABL] Fused 5 > Binary 4

Secure check fail : abl (6)
[Samsung Galaxy S21 Guides, News] Vazovski2007:
That's very strange to be honest, did you backup your phone? If yes than first try to reset phone from settings or just use patched Odin ;-)
[Samsung Galaxy S21 Guides, News] DeathStolas:
Patched Odin gives same problem. Ill try to reset and see what happens.
[Samsung Galaxy S21 Guides, News] Vazovski2007:
Ok, because i have reflashed couple times from u to u1 and back had no problem at all
[Samsung Galaxy S21 Guides, News] DeathStolas:
Same issue and warning. Tried multiple downloads as well.
[Samsung Galaxy S21 Guides, News] Vazovski2007:
Can you try this?

On which firmware you are now? It looks bootloader issue.

As i said i did switch couple times and had no problem.
[Samsung Galaxy S21 Guides, News] DeathStolas:
Im on TMB U firmware.
[Samsung Galaxy S21 Guides, News] DeathStolas:
Tried that as well still no go. Im wondering if possibly bootloader is newer on U (TMB) than it is on U1. Maybe issue? Im not 100 sure.
[Samsung Galaxy S21 Guides, News] Vazovski2007:
That iw your current firmware? An what is which you want to install?
[Samsung Galaxy S21 Guides, News] DeathStolas:
Currently on U was trying to go back to U1.
[Samsung Galaxy S21 Guides, News] Vazovski2007:
No i mean exact firmware versions.

And how do you want to flash? Are you using Home_CSC or Just CSC?

I have flashed u1 to u and also flashed back to u1 and than again to U since VoLTE were not fixed in U1 BUKK
[Samsung Galaxy S21 Guides, News] DeathStolas:
In on latest TMB U. Was trying to go back to latest XAA. And I used just CSC.
[Samsung Galaxy S21 Guides, News] Vazovski2007:
Than i do not understand what is the reason :-( qs you can see on screenshot above I'm also on latest firmware

If ypu will be able to find out reason please share also with us 🙏
[Samsung Galaxy S21 Guides, News] DeathStolas:
I definitely will share if I figure it out. I'll work more on it later.
[Samsung Galaxy S21 Guides, News] prominade:
Guys, my region is XAA, can I change it to PCT?
[Samsung Galaxy S21 Guides, News] Furious Froyo:
I'm currently on T-Mobile with U, but would like to go to U1. I've read the process, but I'm seeing people having issues. Is there a new process or are there still issues?
[Samsung Galaxy S21 Guides, News] sojuzxy:
I have a S21 SM-G991U which is bind to AT&T. Is it possible to flash it to SM-G991U1 (XAA)?
[Samsung Galaxy S21 Guides, News] Vazovski2007:
No since it is locked on AT&T
[Samsung Galaxy S21 Guides, News] sojuzxy:
Even if telco unlock version, i still cant flash it ?
[Samsung Galaxy S21 Guides, News] Vazovski2007:
If your phone is unlocked than you can switch betwwen U and U1 firmwares
[Samsung Galaxy S21 Guides, News] sojuzxy:
ok i tried, i doesnt let me to flash to U1(XAA) but, i flashed it to U(DSH).
[Samsung Galaxy S21 Guides, News] sojuzxy:
I want to ask, after i flashed my phone, can i press factory reset from(settings) the phone? Will it return to the previous software? or it will still be the software version of the one i flashed?
[Samsung Galaxy S21 Guides, News] Vazovski2007:
Yes sure, now you are on other firmware than you had so factory reset will not change firmware version for sure
[Samsung Galaxy S21 Guides, News] Furious Froyo:
I attempted to go from U to U1 and it failed with an error typically attributed to my current U firmware being newer than the U1, although I downloaded the latest U1 firmware. I also attempted with every version of available patched Odin.

Does the bootloader need to be unlocked to move from U to U1? Suggestions?
[Samsung Galaxy S21 Guides, News] jhunkab:
Is there a 5 ATT USERDATA for S21 Snapdragon US? It seems Unlocked version has moved to Bootloader version 5 now - as of Feb, 2022

BL_G991U1UES5BVA6 <-- unlocked

BL_G991USQS5BVA6 <-- ATT, TMB etc.
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
Nope but you do need to check bootloader levels of your current firmware and desired firmware

Yes there is
[Samsung Galaxy S21 Guides, News] jhunkab:
I didn't find BL v 5 ATT USERDATA hosted on the link in OP. Would you be able to share the location where I can get it from? Thanks.
[Samsung Galaxy S21 Guides, News] unarj:
hey there. I'm just getting an S21 from a OnePlus 6 and haven't run a locked bootloader device in many years so likely a silly question, but...

is there some special sauce in the files you posted vs a Frija download? I have a TMO device that I want to carrier unlock (officially) and flash U1 firmware on. do I need to flash the U1 firmware you posted _first_ and then flash the current Frija XAA U1 firmware or can I just jump straight to current?
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
1. Assuming that your device has had a software update done to it in the past year, you won't be able to flash the U1 firmware in the OP, as that's over a year old.

2. Don't flash anything until after it's carrier unlocked
[Samsung Galaxy S21 Guides, News] jake.99x3:
What is the benefit of flashing from U to U1? have my G991U on 3.1 and am bummed about not being able to take advantage of the bootloader exploit/unlock.
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
No bloatware.

Do NOT update your bootloader version. If you're currently on 2 or 3, there's a greater chance of those getting cracked than there is for 4 or 5
[Samsung Galaxy S21 Guides, News] jake.99x3:
Good to hear. I am still running basesband/bootloader version 3 with one UI 3.1 and android 11 (auto update blocked/uninstalled with adb).
[Samsung Galaxy S21 Guides, News] theartialmartist:
Has anyone successfully flashed U1 on a Taiwan/BRI SM-G9910? I currently dont have 5G or Volte options and use ATT here

Yes its a snapdragon
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
Not possible
[Samsung Galaxy S21 Guides, News] robnitro:
Hello,

Anyone on the June or July updates able to run this and see if it works? For U, after cvd update, they have removed this.

Cvf (June) on U broke this application by removing this option to specify lte bands.

App here on play store... Just run it and see if you get a menu.

If not, they have disabled it on U1 cvg.

Network Mode Samsung - Apps on Google Play

Network Mode / Band Selection / LTE ONLY for Samsung

play.google.com
[Samsung Galaxy S21 Guides, News] AsItLies:
I know this one works to select lte only: https://play.google.com/store/apps/details?id=com.teknokia.force4glteonly&hl=en_US&gl=US

I'm on latest update, S21.
[Samsung Galaxy S21 Guides, News] robnitro:
Thanks,

I was able to use an app like that on latest update but not the ability to switch lte bands.

Can you try the other app I linked and see if that one works on latest?
[Samsung Galaxy S21 Guides, News] paltarureru:
hello, can you install the sm-991u1 us rom to the sm-9910 china the 2 snap version?
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
nope
[Samsung Galaxy S21 Guides, News] robnitro:
Does *#2263# give you the menu to select bands for each SIM slot? I found this today, but am using the may update
[Samsung Galaxy S21 Guides, News] habiodunz:
Can my device get permanently bricked if the flashing process is interrupted mistakenly
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
No
[Samsung Galaxy S21 Guides, News] speranio:
Hi all, I have an AT&T S21 5G on G991U, CSC ATT, SW rev 4, and it stopped updating OTA since November 2021, still on Android 11. I couldn't find newer ATT builds online.

Will I be able to flash a 991U build for another CSC which has fresh updates and security patch level, e.g. DSH or DSA or TMB? If i'm only interested in Android system and security updates, do I need to flash USERDATA?

Is it possible to do this without wiping the phone data and apps?
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
The answers to your questions are found in the OP, so clearly you haven't read it yet
[Samsung Galaxy S21 Guides, News] speranio:
Rather I have read the OP many times, and even read all 9 pages of the discussions. Regarding the wiping the OP says both "HOME CSC file keeps data intact" and "for switching from one carrier's firmware to another is: 1. Flash full U1 firmware package including non HOME CSC". And it's not clear if I need to flash U1 with wipe first, or I can go directly to U of another CSC with HOME CSC.

Also I see that in a post on page 8 you said "Don't flash anything until after it's carrier unlocked", which is confusing to me, bc the OP doesn't mention the need to unlocking before any flash. So, could you please answer my questions if they look obvious to you? I guess the answer to the USERDATA question is No, but i'm not sure about wiping and flashing without unlocking.
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
1. If you have G991U firmware and all you want to do is update, then you can ignore anything about G991U1 firmware

2. The post about "Don't flash anything until after it's carrier unlocked" was in reply to a user who wanted to flash U1 firmware. So again, if you don't want/need U1 firmware, then you can ignore that
[Samsung Galaxy S21 Guides, News] Solitaryrex:
I have a U1 with CSC TMB , it's a way to change it to XAA?
[Samsung Galaxy S21 Guides, News] MarvinMod:
Im on U1, android 12, XAA region. No android 13 for my region. All other regions have updated and id like to keep my device less bloated. Anyone have any answers on why there has benn no 13 release for XAA usa unbranded?
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
No one on XDA is gonna be able to answer that. That's something only Samsung knows.

But no U1 firmware has bloatware, regardless of its region. So you can just flash ANY U1 region and have 13 instantly 🤷🏻‍♂️
[Samsung Galaxy S21 Guides, News] burc ugur:
Can I change my csc xaa to xac? so change g991u1 to g991w. this is possible? because caller ID and spam protection are not working. i saw for s21 ultra g998u1 to 998w...

please help me.
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
Yes, you can flash G991W firmware to a G991U1 model
[Samsung Galaxy S21 Guides, News] burc ugur:
which firmware should i download? (sm-991w)

my device this:

And my final question, there is no Turkish language support on this device setup screen, so the phone's settings are always in English. When I add a language from the add language settings, the applications are in Turkish, but the settings and the quick panel remain in English, how do I solve this?
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
1. The same firmware which corresponds to the device's current Android Security Patch Level

2. There is nothing you can do. If you want full Turkish language support, buy a Turkish model of the same device (whichever model is sold by default in Turkey)
[Samsung Galaxy S21 Guides, News] burc ugur:
This does not increase the knox counter, does it? This is not problem for knox alright? (Samsung Pass, Secure Folder and Samsung Health) So Knox 0x?
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
It is impossible to trip Knox by flashing official Samsung firmware. Knox is only tripped when you flash custom firmware
[Samsung Galaxy S21 Guides, News] burc ugur:
thank you i changed csc xaa to xac smart call is now work. but firmware update error why? is it just because i changed csc? so if i installed the full xac rom, wouldn't that be the case?
[Samsung Galaxy S21 Guides, News] iBowToAndroid:
Yes it's because you just flashed the CSC and not the whole firmware