How to restore my IMEI number back to original?

[Hannan Ashraf]

My uncle gave me his Samsung Galaxy Grand 2 a few days back. I was experiencing problems while opening its security settings (Unfortunately settings has stopped working). My uncle told me that it's rooted. Today I unrooted it to its latest stock rom (4.4.2) using Odin on PC but now both sim networks are not working. When I do *#0011# and when I check sim settings, it says that Network is Blocked. Plus When I did *#06# I noticed that the IMEI number of my cellphone is changed. How do I fix it? I want to use cellular services.
More details:
1: I have got the box of my phone and original IMEI numbers are written on it.
2: The country of origin of the phone on the box is Vietnam.
3: I live in Pakistan and I flashed it to original 4.4.2 version released for Samsung Galaxy Grand 2 for Pakistan.

 

[Rukbat]

2: The country of origin of the phone on the box is Vietnam.
3: I live in Pakistan and I flashed it to original 4.4.2 version released for Samsung Galaxy Grand 2 for Pakistan.

Reflash it, using the firmware for Vietnam. The phone doesn't care where it is, it cares what firmware it was built to use. (I assume you mean that the country it was built to be sold in is Vietnam. The country it was built in is irrelevant. China builds phones for use in the US, but if you flash a Chinese ROM to them, they stop working.)