If you cannot find a free download, vendors like KitBazar or LED LCD TV Spares sell the physical pre-programmed ICs or the motherboards directly.
You will need a USB Programmer (like the CH341A or RT809F) to write the data directly to the TV's 8-pin flash chip. Download VST59T PB706 RECONNECT RELEG3206 Backup Dump rar
If the TV still powers on, you can try placing the extracted firmware on a FAT32-formatted USB drive, plugging it into the TV, and holding the Power button while plugging in the AC cord to trigger an auto-update. If you cannot find a free download, vendors
If you obtain the .rar file, it usually contains a .bin file which is the raw data for the SPI Flash memory. plugging it into the TV