Download latest Jelly Bean 4.2 stock firmware for VKworld VKZ200 smartphone from here or here. Download another VKworld firmware from here.
Archive: vkz200 rom
Model: VKworld VKZ200 smartphone
Image file size: 453 MB
Platform: Mediatek MT6592
Caution: Please do not update firmware unless you know what you are doing, you really want it or it is absolutely necessary. Firmware updates may occasionally have bad results, like bricking your device, temporarily or permanently. The firmware update process is done entirely at your own risk. Before attempting to update the firmware, back up your data.