By 2021:

The bootloader prevents unauthorized operating systems from loading.

Flashing a new operating system requires modifying your device's core software. Before beginning, you must prepare your hardware and data.

Search the for your specific device model to find a stable Android 4.4 KitKat custom ROM. Download the ROM .zip file.

Do not check Internal Storage or Micro SD card if your ROM files are stored there. Swipe the slider at the bottom to confirm the wipe. 🚀 Step 6: Flash Android KitKat v4.4 and GApps Now, you will install the operating system files.

Note: Visit the XDA Developers forum, search for your specific device sub-forum, and look for "ROMs" labeled with Android 4.4, KitKat, or CM11. 3. Google Apps (GApps) Package

Only for nostalgia or hardware rescue.