http://antgsm.com/showthread.php?t=155929&highlight=g550t2
Procedure
Root
usb debug
*#0808# and select 'DM+MODEM+ADB
direct unlock
done
Operation: Unlock
Selected model: SM-G550T2
Software version: 33.7
Waiting ADB device... OK
Reading phone info...
Model: SM-G550T2
Android version: 6.0.1
PDA version: G550T2UVU2AQC4
CSC version: G550T2TMB2AQC4
Phone version: G550T2UVU2AQC4
Product code: SM2G550TZKWTMB
CSC country code: USA
CSC sales code: TMB
Phone SN: 00000000000
IMEI: 351722081815387
HW version: REV0.4
RF cal date: 20170317
Chip name: EXYNOS3475
Modem board: SHANNON308
Security patch: 2017-03-01
Boot Warranty bit: 1
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: 19 58 0A A6 92 49 5D 34 16 DA 93 A3 2F A6 5F DF
Calculating... OK
Unlocking... OK
Writing NV data... OK
Rebooting phone... OK
Unlock done
Done with Samsung Tool PRO v.33.7