There are so many ways to flash Android mobile devices available and presented on the Internet, and you can use any process that is compatible with your smartphone's processor. Some require a PC to complete the flashing, but in this tutorial I'm using  SP Flash Tool. 

To flash or install firmware on Infinix Smart 5 X657 (H8030A) factory firmware

1. You need to download and install SP Flash Tool  and USB drivers on your computer. But If you have already installed the tool on your computer, then skip this step.

2. Search or download Infinix Smart 5 X657 (H8030A) factory firmware blow or click here  to view all (Mediatek(MTK) Supported Firmwares). if you have already downloaded  the firmware for your device than extract the zipped file to your computer.

3. Turn off your device for at least 8-9 seconds

4 load the extracted firmware to sp flash tool by clicking on (scatter-loading) 

6. Click start  and connect the phone to your Computer using the USB Cable. on some mediatek devices you will need to hold volume down or up before connecting your phone.

8. The Flash Tool will recognize the phone. if USB drivers where installed

9. The flash tool should Begin the Flashing Process.

10. Once, flashing process is completed you will see the Success Message in the Flash Tool ( download OK )

Congratulations! Now Close the sp flash Tool and Disconnect your phone from the Computer and set it up.