This is best tool for sumsung see inside

[burger_gsm]

UNLOCK INSTRUCTIONS:
Phone must be rooted!
If the software can't root the phone automatically,
then you must root your device manually.
1. Power on the phone.
2. Enable 'USB debugging' in 'Settings'-'Developer options' for Android 4.0 - 4.1.2 or
tap 7 times on 'Build number' in 'Settings'-'About phone' to enable 'Developer options' in Android 4.2+.
3. Connect the phone to PC with USB cable, install drivers if needed.
4. Select device in ADB settings.
5. Press 'Unlock' button for direct unlock.

To reset Google account activation or Samsung reactivation lock:
1. Power on phone in download mode (turn off phone, press vol.down + home + power).
2. Connect phone to PC with USB cable, install drivers if needed.
3. Press 'Reset FRP/React/EE' to deactivate Google/Samsung/EE account activation lock.
4. After phone reboot, go to settings and perform factory reset.

Operation: Unlock
Selected model: SM-G550T
Software version: 28.1

Waiting ADB device...
Please, allow USB debugging on phone... Ok
Reading phone info...
Model: SM-G550T
Android version: 6.0.1
Product code: SM2G550TZKATMB
Phone version: G550TUVU1APF1
PDA version: G550TUVU1APF1
CSC version: G550TTMB1APF1
CSC country code: USA
CSC sales code: TMB
HW version: REV0.4
Phone SN: RV8HA0M73GW
Chip name: EXYNOS3475
Modem board: SHANNON308
Security patch: 2016-06-01
RF cal date: 20161019
IMEI:
Checking Super user right... true
Reading NV data... Ok
Checking NV data... Ok
Reading data... Ok
Detecting MODEM... Ok
Reading MODEM... Ok
Calculating... Ok
Writing zTool... Ok
Initialization zTool... Ok
Running zTool, please wait...
Start... Ok
Initialization... Ok
Generate and check client proof... Ok
Verify proof by client... Ok
Reading data... Ok
HWID: 1C 7B D6 13 06 14 CB 9A FB 11 2A D5 4D 32 72 4E
Calculating... Ok
Unlocking... Ok
Writing NV data... Ok
Rebooting phone... Ok
Unlock done

Done with Samsung Tool PRO v.28.1