There should be AT LEAST two files, "usb_auto_update.txt" and an "mbXX_en.bin" file (XX=65, 85, 90 etc.) There may ALSO be an mboot.bin. (If file is *.exe, run it, and get the files then... do not copy the *.exe to the memory stick, this will not work)
Put these files onto a BLANK, FAT32 ( FAT or FAT16 better) formatted USB memory stick
Unplug the TV power. Connect the stick to the TV.
Plug in the TV while you hold "OK" on the remote control.
In fault mode, LED blinks slowly. If firmware is updating, LED should blink more rapidly for about 1 minute. Release "OK" after you notice the flash code has sped up from normal fault code. (Fault code may or may not be displayed initially.)
If all works, TV will power up with initial setup screen (all settings reset)