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How To Guide [GUIDE] How To Flash Official Samsung Unlocked BloatFree Firmware

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smo02

Member
Jan 3, 2010
11
4
I have a TMB version. I am able to flash XAA firmware (G998U1UEU1AUAJ). However, the software update doesn't work. It shows below message.
Couldn't download update
Unable to update the software. A network or server error occurred. Try again later.
Does anyone have this issue?

It's working today when I tried again.
 

smo02

Member
Jan 3, 2010
11
4
I just got my ATT Ultra and and have tried this several times and it failed. I haven't used odin since the S4. Does USB debugging need to be on? The first time SHA failed, restart odin and flash fails. Then it continues to fail after. What else can I do or would a different version of Odin be better? ATT guy, chime in. thx

What's the error? Did you use the patched ODIN? If you can post a screenshot, it will be helpful.
 

qoupan

Member
Mar 12, 2021
9
1
I just received my S21 Ultra AT&T version but I am using Cricket wireless yesterday. I purchased it from samsung.com with full payment. I know I should buy the unlocked version, but the 256GB one I want is out of stock, so I have to buy the AT&T version. I turned on the phone last night but I did not insert cricket sim card. I updated the system and all softwares. I found there are a lot of AT&T bloatwares, but I do not need them acturally. So I plan to flash it with the XAA firmware. Before I do it, I have following questions:
1. If I flash the AT&T version with XAA firmware, does it also mean I unlock this phone? It could be used under other carriers (T-mobile, verizon and soon)?
2. If the flash does not unlock the phone, how do I unlock it? Ask samsung or AT&T to unlock it?
Thank you so much. Any responses are appreciated.
 
DONT FLASH ANYTHING YET.
You will need to sim unlock it first.
As you did not get the unlocked version BL unlock will not be possible till after a hack is found.
Go here to sim unlock the phone
Select unlock a phone
Then when asked if you a att customer say no.
Enter imei and follow the prompts.
Then check you email ATT will send youa confirmation email you will need to follow the link to confirm within 12 hours
Then att will either remote unlock the device or send you a simcode.
Once your sim works on the phone with no issues then flash xaa
 
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qoupan

Member
Mar 12, 2021
9
1
DONT FLASH ANYTHING YET.
You will need to sim unlock it first.
As you did not get the unlocked version BL unlock will not be possible till after a hack is found.
Go here to sim unlock the phone
Select unlock a phone
Then when asked if you a att customer say no.
Enter imei and follow the prompts.
Then check you email ATT will send youa confirmation email you will need to follow the link to confirm within 12 hours
Then att will either remote unlock the device or send you a simcode.
Once your sim works on the phone with no issues then flash xaa
Thank you. I'll let AT&T to unlock my phone first.
 

brholt6

Senior Member
Oct 10, 2013
1,391
441
Thanks OP! Been out of the game for awhile, but everything went smoothly on my Verizon S21 Ultra. It appears everything is working except for RCS as I'm unable to get chat features in Samsung Messages to appear as an option. It looked like others had this outcome but I didn't see anything related specifically to Samsung Messages. I'm assuming this is Verizon's way of pushing their phone/firmware.
 

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Shuthefrontdoor

Senior Member
May 15, 2012
651
147
I flashed the u1 firmware on my tmo s21u and all my tmo stuff is gone and I have samsung native spam caller protection but when I check about phone it still shows tmb/tmb/tmb is that normal? I though it would of changed to tmb/xxa/xxa or something of that nature.
 

jeffsga88

Senior Member
Jan 5, 2016
842
666
OnePlus 9 Pro
I flashed the u1 firmware on my tmo s21u and all my tmo stuff is gone and I have samsung native spam caller protection but when I check about phone it still shows tmb/tmb/tmb is that normal? I though it would of changed to tmb/xxa/xxa or something of that nature.

I have the same issue. I flashed the XAA U1 firmware and it stays on tmb/tmb/tmb. No matter what I've tried, I haven't been able to get that to change to XAA. Phone is unlocked, other sim cards work but the only CSC change that will happen is change from tmb to Sprint when inserting a Sprint sim card in the phone. I've instead a Verizon sim card and it stays tmb, which unfortunately means Verizon bands and CA not working properly. Does anyone have any idea how to properly change the CSC?
 

LunnBdx

Member
Feb 18, 2016
16
6
Hey boys,

Just quick question : is it possible to swap to Exynos CSC (XME, in my case), if we get a Snapdragon variant, after flashing to clean firmware ?

I am currently in Exynos country, and this trusted seller is offering SD888 variants (SM-998U) at lower price than local Exynos.
My plan is to get S21U (I believe it comes with VZN firmware), then flash it with clean de-carriered firmware from OP, then swap this clean firmware to my local CSC. Hence my question above.

I used to do a lot of firmware flash and CSC swaps in the past (Galaxy Note 8 was my last Samsung), but never tried to set a CSC from Exynos region on a phone meant for the Snapdragon market.

Thank you for your help, beautiful people
 

insang-droid

Senior Member
Sep 24, 2013
326
134
I keep getting shh256 error,. I tried doing Odin 3.14.1 modified as well and I get sw mismatch the download screen on the phone.. Im on the latest TMB update.

Tried the both csc

Any ideas?
 

Skander1998

Senior Member
May 23, 2012
1,610
607
26
Doha
Samsung Galaxy Note 3
Samsung Galaxy S7
Hey boys,

Just quick question : is it possible to swap to Exynos CSC (XME, in my case), if we get a Snapdragon variant, after flashing to clean firmware ?

I am currently in Exynos country, and this trusted seller is offering SD888 variants (SM-998U) at lower price than local Exynos.
My plan is to get S21U (I believe it comes with VZN firmware), then flash it with clean de-carriered firmware from OP, then swap this clean firmware to my local CSC. Hence my question above.

I used to do a lot of firmware flash and CSC swaps in the past (Galaxy Note 8 was my last Samsung), but never tried to set a CSC from Exynos region on a phone meant for the Snapdragon market.

Thank you for your help, beautiful people

This is not something you can do - you may not use Exynos CSCs in Snapdragon models.
 

FrozenCrunch

New member
May 19, 2021
3
0
Whoops. Meant to post this here:

Hi there!

I haven't been on XDA in a long time (used to lurk back in the HTC Hero days).

I recently found out that a second-hand 21 Ultra that I bought is actually a VZW branded model, but it is fully unlocked (IMEI has been checked). I have T-Mobile. I've read through the OP and it looks straight forward enough (well written guide, by the way).

Is there anything special I need to do to ensure I get all the T-Mobile features working?

I'm quite comfortable with using Odin, just want to double check if there's any "gotchas" to be aware of.

I have no interest in unlocking my bootloader, just want to be on the official Samsung non-carrier ROM, have all my carrier-based features (wifi calling/RCS) and get my updates straight from Samsung. I should also mention I have a grandfathered T-Mobile plan and I have no account-based restrictions like tethering or anything. It sounds like this will do the trick, but I just want to make sure.
 

daweeze02

Senior Member
Jul 10, 2009
532
34
Sorry if this was already answered but I've been out of the flashing game for a few years now.

Quick synopsis
Verizon sim unlocked s21 - switched to tmobile 5g sim
No issues with 5G but is there any benefit to flashing from the U to the U1 firmware in terms of performance besides debloating?

Will going from csc vzw to tmb make any major impacts in terms of signal strength?
If not I see I can flash home csc so I don't have to wipe. I have tons of work software so it would be a major pita to reinstall them all and relogin etc


Reason I ask about the signal is on my moto g old phone I will get band 66 with my tmobile sim card
On my s21 in certain areas I get stuck on band 2 and it forces me to edge


Thanks
 
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  • 12
    Did you just get your shiny new S21 Ultra? And the first thing you noticed is tons of preloaded carrier apps that can't be deleted? This is how to fix that.
    Convert your phone into the one that would come from Samsung directly with a simple firmware flash!

    BACK UP YOUR PHONE! ALL DATA WILL LIKELY BE WIPED!
    You will need an SM-G998U/U1/W
    Computer running Windows
    USB-C Cable for your PC to Phone

    This is only for SM-G998U/U1/W

    Step 1:

    Download the ROM of your choice. The firmware number does NOT need to match your phone, as long as you have an SM-G998U/U1/W
    From each link, click the latest firmware in the list (what ever the top one is) and on the page that loads, click the blue button that says "Download from website"
    (You can only download one in a 24 hour period so choose U1 or W wisely)
    SM-G998U1 (U1 is unlocked, no carrier bloat, US radio bands)
    SM-G998W (W is unlocked, no carrier bloat, Canadian radio bands)

    The only main difference between the two is the Canadian W Firmware supports all radio bands aside from (n260, n261), the file size is a little bigger and will take up a fractionally larger amount of space on your phone as a result of also including all CSC's, but will allow your device to connect to any tower frequency with the correct SIM.
    The U1 Firmware supports all US bands and works across all Canadian carriers, but does not have any Carrier CSC's as a result of the smaller file size.
    Thanks to @milan03 for the info

    Best measure is to use the W Firmware as it will be supported, but if you are positive of your carrier will work and bands are the same as US carriers, use the U1 to save some space.

    Step 2:
    Download Odin 3.14.4 and Samsung USB Drivers

    Step 3:
    Extract all of the .zip files that you have downloaded, and install the Samsung USB Driver

    Step 4:
    On your S21 Ultra, enter download mode by turning the phone completely off.
    Once the phone is off, hold the volume up AND down at the same time, and without letting go of those buttons, plug a USB cable in from the computer to the phone
    Do not let go of the volume buttons until the Download Mode screen is displayed.

    Step 5:
    Open Odin and make sure the S21 Ultra comes up as one of the COM ports
    If it doesn't try rebooting your computer, and then connect your phone again

    Step 6:
    Click the BL Button, and select the BL file you extracted from the Firmware .zip
    Click the AP Button, and select the AP file (This will take awhile, do not touch anything, don't even click your mouse or try to do anything else on your computer, it can crash, just wait, make a coffee or something, because depending on your computer specs, it can take up to 5 minutes to load that file
    Click CP and add the CP file
    Now this last part here, you have a choice, however I strongly recommend you do not choose the second option at this time, however you CAN, but you might face stability issues.
    When clicking CSC, you can EITHER add the CSC file, which is what I recommend, OR you can add the HOME_CSC file.

    The differences between these files is that the CSC file will wipe your phone, but this is recommended, because when you are switching firmware's from a different carrier build, which we are right now, you want to delete anything left over that could conflict with the new firmware being flashed, however, you CAN flash HOME_CSC which will keep all of your user data on the phone, but this could leave old firmware files behind that could cause stability issues with your phone, crashes, force close apps, or even boot loops.
    It's recommended to ONLY use HOME_CSC when you are UPGRADING on the same build (eg, if you are on SM-G998W and UPGRADING to another SM-G998W firmware)
    So if you are going from U/U1 to W, it's recommended to use CSC, if you are going from W to W, Home_CSC should be fine, if you are going from W to U1, you should use CSC.

    Step 7:
    Once you have made your choice of either CSC or HOME_CSC, you can now click Start and it will start flashing the new firmware.
    This process will take a fair amount of time, go relax and enjoy that coffee you made while the AP file was loading.
    Once the flash is done, it will say Pass in green, and your phone will reboot automatically into your new official carrier bloat free firmware.
    If you picked CSC, you can now setup your phone just like a new phone and restore your backup, if you picked HOME_CSC, you should be at your lock screen, and the phone is ready to use.

    Congratulation, you are now on the Official Samsung Firmware with no carrier bloat as if you bought the phone directly from Samsung.

    Troubleshooting:
    If you used CSC and the phone did not pass and says FAIL, try the flash again with HOME_CSC, once the flash passes, you should be back at the lock screen, go to settings, search for reset, and do a factory reset, wipe all data because something did not flash correctly the first time so you need to wipe the phone after the successful flash to guarantee no stability issues.

    If you used HOME_CSC and the phone did not pass, use CSC and the phone will be wiped when it flashes, and you need to set up your phone like new and restore your backup during the setup screen.

    If it still fails to flash both CSC and HOME_CSC, Download Mode probably timed out from your computer taking too long, at which point, you can try doing Step 6 BEFORE Step 5.
    Turn your phone off completely, load all of the files into Odin, THEN enter Download Mode and immediately click Start to start the flash. This will give you a little more time for your computer to make the flash and hopefully download mode will not timeout, if it still fails, try a faster computer or a different/shorter USB cable.

    If you are with Bell in Canada and you did not get the pre-order bundle promo E-voucher prompt from Samsung Members App, flashing the SM-G998W firmware linked above will fix this and you can redeem your e-voucher and get your headphones and smart tag.

    This is a video I made on the S20 Ultra for flashing One UI 3.0 Beta/Stable, however the process is identical, just use the files from here instead of the ones linked in the video description
    I will be replacing this video with a dedicated S21 tutorial once I have have finishing editing the new video, but for now this will give you an idea of how it works until 5:30 in the video, after that it's mostly related to One UI 3.0 Beta/Stable for the S20 so there's no need to watch further than that as the S21 would be done by that point in the video.
    2
    So will this trip KNOX? My phone should get here next week (AT&T), and one of the first things I always want to do is get rid of the bloat.
    No problem with KNOX.

    But majority of bloatwares are issued of CSC carrier brand and it is impossible to change csc without root or using samkey...
    So this firmware will be like other versions with same samsung apps unless I'm wrong.
    2
    Thanks for the guide.

    If I may, I'd like to post a correction on the state of the supported frequency bands on Canadian and the US firmware:

    - The U1 firmware doesn't only support T-Mobile bands, it also fully supports AT&T and Verizon frequency bands, which includes their unique LTE carrier aggregation combinations as well as the 5G non-standalone combinations with n5 and mmWave. That's in addition to T-Mobile's combos with n71 and n41, in both non-standalone and standalone environment.

    - At the same time the Canadian W firmware doesn't support all 5G bands, it completely disables mmWave (n260, n261), which means the US devices with this firmware won't be able to access this super-fast flavor of 5G on any US network. It also doesn't fully support all US 5G non-standalone combinations in FR1 (Sub-6 GHz) range.

    Thanks again.
    1
    it is impossible to change csc without root or using samkey...

    If you're running a multi csc firmware (the one's linked above) you can change your csc by opening the phone app and dialing *#272*YOUR IMEI NUMBER# and from there you can pick the firmware CSC and carrier CSC to be whatever preinstalled apps you want. The W firmware has all of the preinstalled which is why the file size is larger.

    As for the Samsung bloat, they all come with it, but a lot of these should be able to be removed using ADB without root.

    There are some ADB scripts around that some skilled people wrote for removing bloat apps in bulk through ADB without root.
    1
    I got a VZW S21 ultra and was thinking of doing this. Do all of the Verizon features work, like wifi calling, hd voice, rcs? and unlocked features like caller id, samsung cloud, call and text on other devices?
    Wi-Fi calling in volte work. Samsung caller id it there and I was able to configure it. Cloud was as well. Call and text is and I configured it but my tablet does not support it yet.