How do I flash and reinstall Android OS?

Now, it’s time to flash the ROM:

• Reboot your Android device and open the recovery mode.
• Navigate to the ‘Install ZIP from SD card’ or ‘Install’ section.
• Select the path of the downloaded/transferred Zip file.
• Now, wait until the flash process gets finished.
• If asked, wipe out the data from your phone.

What is meant by flashing an Android phone?

“Flashing a custom ROM” basically means to load a different version of the Android OS. This site actually explains it very well. A custom ROM is the full Android OS customized by the ROM builder usually to make it faster, provide better battery-life or add new features.