How To Guide Unlock bootloader and root A125U u3

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marioz17

Member
Sep 4, 2017
28
13
piedras negras, coahuila
Requirements:
-Tested working on firmware A125USQS3BVA2
-A MTK bootloader unlocking tool, tested working with UnlockTool
-This is for A125U on binary 3 ONLY

Special thanks to @Boster27 for translate guide and test method


Steps:

1- Boot into Download Mode (vol+ & vol- & pwr) and flash this custom BL file BL_A125.tar with ODIN patched using the BL button. The device will reboot to an error screen, this is normal.

2- Boot into BROM mode using Test Points (picture attached, needs light dissasembly). Using UnlockTool or your MTK tool of choice, head to the Samsung section and select A125, then on the BROM tab, choose Unlock Bootloader.
After this the device should reboot into recovery and perform a factory reset automatically. In case it doesn't, go into recovery manually (vol+ & pwr) and perform a factory reset. After this the device should boot normally.

3- Once the setup process is complete, connect to Wifi and enable Developer Options to confirm that OEM Unlock is enabled and unlocked. Install the latest version of Magisk Manager and use it to patch the AP file for the corresponding firmware.

4- Boot into Download Mode, make sure the AutoReboot option is unchecked in ODIN, and flash the magisk_patched.tar AP file, and the stock CP, CSC and USERDATA files. Then manually boot into recovery and perform a factory reset. After this the device should boot normally.

5- Once the setup process is complete again, connect to Wifi and enable Developer Options to confirm that OEM Unlock is still enabled and unlocked. Install the latest Magisk app and launch the app.
It should show a dialog asking for additional setup. Let it do its job and the app will automatically reboot your device.

And done! Phone is rooted on binary 3!
 

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mfeliu07

Member
Mar 17, 2009
37
1
Habana
Hello
Thanks for the input.
I have a problem when I write the BL_A125.tar it bricks and I can't get into recovery mode to do a wipe.
Attached image of the error.
Thank you

WhatsApp Image 2022-04-17 at 11.35.09 AM.jpeg
 
Last edited by a moderator:

Wish39

Senior Member
Jan 13, 2015
201
55
i need the phone to test but you can try if the phone can enter BROM mode with testpoint
Ok when I get one then I will try. Do you also have a unlockable BL for the Galaxy A21 (A215U, A215W, A215U1, S215DL)? I have a S215DL that I can test for that, but it is on binary 6.
 

timandolly

Senior Member
Jun 9, 2021
124
25
Verizon Samsung Galaxy Note 4
You write the BL_A125.tar, disconnect the battery and unlock the booloader, after this it enters without problems and is deleted.
If it doesn't, disconnect battery and force enter recovery with volume up and power, do a factory reset
Thanks for helping. I rooted 4 note 4s and they all finally give out so I am going to try a newer phone
 
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  • 2
    Requirements:
    -Tested working on firmware A125USQS3BVA2
    -A MTK bootloader unlocking tool, tested working with UnlockTool
    -This is for A125U on binary 3 ONLY

    Special thanks to @Boster27 for translate guide and test method


    Steps:

    1- Boot into Download Mode (vol+ & vol- & pwr) and flash this custom BL file BL_A125.tar with ODIN patched using the BL button. The device will reboot to an error screen, this is normal.

    2- Boot into BROM mode using Test Points (picture attached, needs light dissasembly). Using UnlockTool or your MTK tool of choice, head to the Samsung section and select A125, then on the BROM tab, choose Unlock Bootloader.
    After this the device should reboot into recovery and perform a factory reset automatically. In case it doesn't, go into recovery manually (vol+ & pwr) and perform a factory reset. After this the device should boot normally.

    3- Once the setup process is complete, connect to Wifi and enable Developer Options to confirm that OEM Unlock is enabled and unlocked. Install the latest version of Magisk Manager and use it to patch the AP file for the corresponding firmware.

    4- Boot into Download Mode, make sure the AutoReboot option is unchecked in ODIN, and flash the magisk_patched.tar AP file, and the stock CP, CSC and USERDATA files. Then manually boot into recovery and perform a factory reset. After this the device should boot normally.

    5- Once the setup process is complete again, connect to Wifi and enable Developer Options to confirm that OEM Unlock is still enabled and unlocked. Install the latest Magisk app and launch the app.
    It should show a dialog asking for additional setup. Let it do its job and the app will automatically reboot your device.

    And done! Phone is rooted on binary 3!
    1
    I was able to do it, thanks.
    I wrote full firmware, wiped and started from scratch, everything went ok, thanks
    1
    You write the BL_A125.tar, disconnect the battery and unlock the booloader, after this it enters without problems and is deleted.
    If it doesn't, disconnect battery and force enter recovery with volume up and power, do a factory reset
    Thanks for helping. I rooted 4 note 4s and they all finally give out so I am going to try a newer phone
    1
    Do you mean A21 or A12? please clarify what model phone you're referring to.
    I do mean A21 as I own one, it was only sold in the USA and Canada. It has the same CPU as the A12.