1.Flash Modem
2.Than Unlock
Modem Link
2. Run 'Calculator' and type +30012012732+.
3. Type *#0808# and select 'DM+MODEM+ADB'.
Searching Samsung modem... detected COM35
Reading phone info...
Model: SM-T377A
AP version: T377AUCS3BRE1
CSC version: T377AATT3BRE1
CP version: T377AUCU3ARD1
Product code: ATT
Phone SN: R52H701M7WH
IMEI: 353608072109864
Unique number: CAJ03AD51FEA063
Reading IMEI... OK
IMEI: 353608072109864 (SIGN: OK)
Reading data from phone... OK
Unlocking... OK
Rebooting phone... OK
Unlock done
Done with Samsung Tool PRO v.34.8
2.Than Unlock
Modem Link
2. Run 'Calculator' and type +30012012732+.
3. Type *#0808# and select 'DM+MODEM+ADB'.
Searching Samsung modem... detected COM35
Reading phone info...
Model: SM-T377A
AP version: T377AUCS3BRE1
CSC version: T377AATT3BRE1
CP version: T377AUCU3ARD1
Product code: ATT
Phone SN: R52H701M7WH
IMEI: 353608072109864
Unique number: CAJ03AD51FEA063
Reading IMEI... OK
IMEI: 353608072109864 (SIGN: OK)
Reading data from phone... OK
Unlocking... OK
Rebooting phone... OK
Unlock done
Done with Samsung Tool PRO v.34.8