You should not download this file for fun. You only need it in specific, critical situations:

On Linux/macOS, you forgot sudo. On Windows, run Disk Imager as Administrator. Also, ensure the SD card isn’t mounted or opened in File Explorer.

The .img may be 3.9GB, while a “4GB” SD card is actually 3.7GB. Use an 8GB card – the image will only occupy the first 4GB, leaving the rest unused.

Critical note: Writing an .img file will destroy all data on the destination SD card. Double-check the drive letter.