The essay title’s emphasis on the word "new" is ironically critical. Because Pioneer ceased supporting the BDP-450 years ago, you cannot find v5.10 on Pioneer’s official website. Instead, the "new" download refers to re-uploads by the AV community on forums like AVForums, HiFiDz, or VideoHelp.
For custom firmware, it is always recommended to update via USB rather than the "Update via Network" option in the menu. pioneer bdp 450 firmware 510 download new
Never power off the unit while the progress bar is moving. The essay title’s emphasis on the word "new"