Repair IMEI S6313T

Hi.
I’m trying to repair IMEI of a Samsung S6313T. But Samsung Tool 20.5 does not recognize the device if I use the "Repair" function. Drivers are ok, modem port is selected, device is rooted:

Operation: Repair
Selected model: GT-S6313T
Software version: 20.5
Reading phone info… no answer from phone
Done with Samsung Tool v.20.5

But the weird thing is if I use the Reset EFS option, the software does recognize the device:

Operation: Reset EFS
Selected model: GT-S6313T
Software version: 20.5
Waiting ADB device… OK
Reading phone info…
Model: GT-S6313T
Android version: 4.1.2
Product code: GT-S6313ZWPZTO
Phone version: S6313TVJAMI1
PDA version: S6313TVJANB1
CSC version: S6313TZTOANB1
CSC country code: Brazil
CSC sales code: ZTO
HW version: MP 0.300
Phone S/N: 00000000000
Modem board: MSM7225A
RF cal date: 2013.11.01
IMEI: xxx
Checking Super user right… true
Backuping EFS… OK
Reseting EFS… OK
Rebooting phone… OK
Done with Samsung Tool v.20.5

There must be a problem with the Samsung Tool software. What’s wrong?