It is not a hardware fault. IMEI is a file in root. use imei writing tool and write the original imei.
Try below steps,
In the dialer , type- *#197328640# or *#*#197328640#*#*
>You will be prompt into the Command mode, On the screen provided , Select on Common , normally option 6
> Now Select (FTM) Option 1
>FTM is for debugging and testing .,(Field Test Mode)
>If (FTM) is on, you will have to turn this OFF
>As soon as your turned this off your NULL or altered IMEI number will be restored