Sites like Dr-Bios or GsmForum often host "bin" files and split firmware archives for repair technicians. You can check for model-specific threads on Dr-Bios .
Turn off the TV, plug in the USB, and turn the TV back on. Some models will auto-detect the update. Download TOSHIBA 40L5400ZE Firmware part4 rar
Format a USB drive to FAT32 and copy the extracted file to the root directory (not inside a folder). Update Process: Sites like Dr-Bios or GsmForum often host "bin"