How does the SU-42118-6 error impact system software updates, and what's the workaround for updating?

The SU-42118-6 error often prevents system software updates from completing because the update process can include checks or interactions with the Blu-ray drive, and if it's faulty, the update fails. The primary workaround is to perform a manual system software reinstallation or update via a USB drive. Download the full system software update file from PlayStation's official website onto a FAT32-formatted USB, then boot your PS4 into Safe Mode and choose 'Update System Software' (Option 3) to install it from the USB. This bypasses the need for the console to verify the update through its internal mechanisms that might be failing.