To recap, the only safe and reliable is found via the official Philips support portal. Never trust third-party websites. Follow the USB manual update method carefully, and your 55-inch 4K TV will continue delivering smooth performance for years to come.
Generally no. Philips prevents downgrading to avoid security risks. philips+55put6002+56+software+update+link
Instead of chasing a firmware file that might not exist or might brick your TV, sever the "Smart" dependence. To recap, the only safe and reliable is
The primary source for all firmware, drivers, and manuals for this model is the Philips Support Page for 55PUT6002/56 . On this page, you can find: you can find: