Once you have the .rar file, you cannot simply plug it into the TV. Follow these steps:
Download Information of TV for Asia, Oceania, Middle East and Africa
If you are trying to fix a "boot loop" or a "blinking red light," you might need a specific rather than standard firmware. Are you currently experiencing a specific error code or a black screen?
Ensure the file is in the root directory and the SD card is under 32GB (older models sometimes struggle with larger "SDXC" cards).
Most Panasonic models will automatically detect the update. Press OK when asked to begin the installation.
Ensure the file matches "TH-L32C4G" exactly.
Never power off the TV during the update. It may take up to 3 minutes, and the screen might go black temporarily.