Samsung S4 AT&T I337 4.4.4 Unlock done.... 
Selected model: I337
Selected port: COM274 SAMSUNG Mobile USB Serial Port
Selected port speed: 115200
Searching ADB device...
Please, allow USB debugging on phone... OK
Reading phone info...
Model: SAMSUNG-SGH-I337
Android version: 4.4.4
Product code: SGH-I337ZKAATT
Phone version: I337UCUFNJ4
PDA version: I337UCUFNJ4
CSC version: I337ATTFNJ4
IMEI: 359721053831689
Phone S/N: R38F301C1LZ
Checking Super user right... true
Backuping MMCBLK... OK
Checking phone at COM274
Detected ID: 00000FE8 (APQ8064)
SW Version:
Reading ESN... OK
Backuping RFNV... OK
Backuping Feature Mask... OK
Backuping NV Item... OK
Backuping Provisioning Item Files... OK
Writing data to phone... OK
Rebooting phone... OK
Waiting phone... OK
Reading phone info...
Model: SAMSUNG-SGH-I337
Android version: 4.4.4
Product code: Not Active
Phone version: I337UCUFNJ4
PDA version: I337UCUFNJ4
CSC version: Unknown
IMEI: Unknown
Phone S/N: R38F301C1LZ
Bypass MSL... OK
Unlocking... OK
Reading QCN file... OK
Checking phone at COM274
Detected ID: 00000FE8 (APQ8064)
SW Version:
Checking paths... error
Restoring EFS Backup... OK
Restoring NV Items... OK
Restoring Provisioning Item Files... OK
Reseting... OK
Unlock done
Done with Samsung Tool v.19.1