If you encounter issues during the firmware installation, consider the following:
Always get the firmware from Sony’s official servers – never from third-party sites.
The safest and only legal way to obtain the firmware is directly from Sony. You should never download firmware files from third-party "ROM sites" or unofficial mirrors, as these can contain malware or corrupted files.
Confirmation: Once finished, a message will appear confirming the firmware was successfully installed. Why Do You Need to Update Firmware?