Use an empty USB flash drive formatted to FAT32 .
Never turn off the TV while the progress bar is moving. 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. Use an empty USB flash drive formatted to FAT32
Alternative region link (if above does not work): Go to https://www.philips.com/support → Search “55PUT6002/56” → Select your country/region. philips+55put6002+56+software+update+link
To update the software for your Philips 6000 series 4K Ultra Slim Smart LED TV (55PUT6002/56)