1. Rooted Phone
2. Root File Explorer (I personally use ES File Explorer)
3. Hex Editor (It's available on Play Store)
!!!Important: Take backup of your IMEI both sim!!!!!!
1. First go to Settings>WLAN>Advanced and note down your MAC Address (it will be in a format like xx:xx:xx:xx:xx:xx)
2. Now open your root file manager..
Copy file "WIFI" and "WIFI_CUSTOM" to your SD card.
3. Open "WIFI" file in Hex Editor.
4. Locate starting of your MAC in it.... (It must be in 2nd line)
5. DO NOT CHANGE FIRST THREE SETS OF MAC ADDRESS.... Now you can change last 3 sets...
6. Now save file...
7. Overwrite this file with original in data/nvram/APCFG/APRDEB/
8. Reboot your phone...
It's done!!!!! Check your Mac address in advanced WiFi menu......
Hit thanks if it helped you.....