How to repair imei of this phone
 

i have one from which from china it was working fine in china but now in africa not working its showing No service

then i chk IMEi Number it showing null/01

Then i take info of that phone by Box it showing this


Definition Applied
1. Power Off Phone , Remove Battery, Insert Battery Back
2. Insert USB cable. In some cases Required Hold BootKey
3. Use Miracle Boot Key In cases Boot key not Find
4. Battery Should be Charged more then 50%
Waiting for USB Port...
Set PreLoader USB VCOM Port (COM39)
Please Hold "ON" to connect with the phone...
Connected to Phone.
CPU: MT6582 SW:0001 Ver: CB00
Downloading Boot8 ...
EMMC Size: 0x01D3000000
Flash Type: EMMC
INT/EXT RAM Size: 0x20000/0x40000000
Reading infr(EMMC)...
BT_ADDR:000046658201
WIFI MAC:000000000000
IMEI1:FFFFFFFFFFFFFFF
IMEI2:FFFFFFFFFFFFFFF
id:S109_EN_V0.0.8
version:5.0.2
model:SM-G920
brand:samsung
manufacturer:samsung

Please any one help me how to repair this phone
Thank you