Yes sure, now you are on other firmware than you had so factory reset will not change firmware version for sure
G991U and G991U1 Firmware Links and Flashing Discussion Here
- Thread starter iBowToAndroid
- Start date
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?
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?
Does the bootloader need to be unlocked to move from U to U1? Suggestions?
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.
Nope but you do need to check bootloader levels of your current firmware and desired firmware
Yes there is
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.
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?
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
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.
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
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).
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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 -
9For those who aren't already aware, G991U is the model number of all of the US carrier versions of the S21. The G991U1 is the model number of the same device, but sold by Samsung SIM unlocked and with no carrier bloatware. Firmware is 100% interchangeable among these models: any U or U1 firmware version can be flashed to any U or U1 device at any time, assuming that you're not trying to downgrade the bootloader. A "U to U" or "U1 to U1" flash does not require a factory reset, but changing from one firmware to the other will require one. Also, U firmware is identical for the 4 base files (AP, BL, CP, CSC) for each individual build, no matter which carrier it comes from. So if you download 2 different carrier versions of the exact same build, the 4 base files will be identical. Where the firmware differs is in the USERDATA file - that's where the carrier bloatware and customizations reside.
Manual Odin flashing is designed for those who:
- want to manually update to a newer version of U firmware on their U device, either because they don't want to wait for their carrier's OTA or because OTAs aren't working on their device, or a different carrier got a new feature/patch before they did
- want to flash U1 firmware to their U device
- want to convert from U1 firmware to carrier U firmware
- want to convert from one carrier's U firmware (with all apps and bloatware) to a different carrier's U firmware (with all apps and bloatware)
For those who aren't already aware, anyone can now download firmware for almost any Samsung device any time that they want, via the various firmware download tools posted here on XDA like SamFirm or Frija. There are threads and info about them here on XDA so I won't waste time explaining - do a search if you're not already familiar with these tools. But they only provide whatever the latest/newest/current version is - nothing older. I pay for a subscription to a site that gets the official releases (usually) before they hit the firmware download tools, so that's where my files come from.
This is not a "beginner's guide to Odin flashing" -type post/thread, so I won't list basic, step-by-step flashing instructions. My threads are geared towards those who already know what they're doing. If you're new to manually flashing Samsung firmware (or haven't done it in a long time), I recommend you consult one of those "beginner's" guides- there are tons of them here on XDA.
Happy flashing!
U firmware: https://www.androidfilehost.com/?w=files&flid=322084
U1 firmware: https://www.androidfilehost.com/?w=files&flid=322085
Notes:
- DON'T QUOTE THE OP WHEN YOU REPLY, kthx
- I have lots of threads just like this one for other Samsung flagships, if it interests you. For those who have already made use of my previous threads for a different device and are upgrading to an S21, welcome back
- My zips are compressed extra small for space and bandwidth savings. The default Windows extractor can't handle it, so you'll need a 3rd party tool like 7zip, WinRAR, etc
- it's quite time consuming to download the files, zip them up, and upload them to AFH. And, I do threads like this for every single Sx and Note x model - so I won't be uploading every single version. The only full builds that I upload are ones where I get access to a new bootloader and/or Android version early, before they hit the firmware download tools.
- My naming method for folders on AFH is: build - bootloader - Android version
So "SAT - 1 - 9.0" means the full build number ends in SAT, it's bootloader version 1, and it's Android 9.0. When bootloader and Android versions increment, the first build to have those changes will have its folder notated appropriately.
- HOME CSC file keeps data intact; using the other CSC will wipe data. Flashing USERDATA will also wipe data.
- Since AT&T doesn't allow their firmware to be publicly available (for any of their devices), I'll try to always upload at least one USERDATA per bootloader increment for AT&T (and Cricket, if they get this model). I'll also upload any full builds if AT&T is the only carrier to get that specific build, because you won't be able to find the files anywhere else.
- For identifying USERDATAS, and to know what region/CSC to use in the firmware download tools if you're downloading yourself:
AIO = Cricket (not available via firmware download tools)
ATT = AT&T (not available via firmware download tools)
BST = Boost Mobile
CCT = Xfinity Mobile (Comcast)
CHA = Spectrum Mobile (Charter)
SPR = Sprint
TMB = T-Mobile
TMK = Metro PCS
USC = US Cellular
VZW = Verizon (available via firmware download tools, but Manual Entry is required - Auto will not work)
XAA = U1 firmware
- the correct procedure for switching from one carrier's firmware to another is:
1. Flash full U1 firmware package including non HOME CSC
2. Upon boot, insert a SIM of the carrier whose firmware you want
3. Watch for the popup that says "reboot to apply new carrier settings" etc, and do it
4. After that restart completes, reboot back to Download mode and flash the full U firmware package, with the USERDATA file of the carrier whose firmware you want2Initial U firmware and AT&T USERDATA are posted, along with U1 firmware. U firmware is not yet accessible in the firmware download tools like SamFirm and Frija, but if anyone wants a different carrier's USERDATA (for flashing bloatware to a U1 device or for converting a U device from one carrier's bloatware to a different one), let me know and I'll get it for you2Thanks for the firmware links!
Odin blocks flashing from U to U1 or U1 to U. To successfully flash: Use the patched/modded odin found here.
realbbb
Sinker Slime1Hey guys, I'm curious if anybody could help me fix an issue I'm having with flashing. I'm trying to flash from the U variant to the U1 but it seems to be csc locked to TMB. I've tried multiple firmwares, pulling the sim out before flashing and even flashing back and forth from U to U1 I can't seem to get the carrier update pop-up at all. I'm kinda at a loss and would appreciate any help you guys could give me
