Now Enjoy Kitkat 4.4.2 (Beta Version) on Your Walton Primo GH2
2. Open Flash Tool
3. Open Download Agent and select MTK_AllinOne_DA
4. Open scatter_loading and select scatter file
SW—> WBW6803WA_0410_T8142 MT6577_Android_scatter_emmc
5. Click Firmware->Upgrade and connect USB cable with mobile (mobile must be off)
6. Then start downloading..
7. When it shows Firmware Upgrade , then installation is completed.
NB: Any Kind Of Damages I am not Responsible. Do At your own risk.
Source : Waltonforum