Because this specific model (40L5400ZE) is part of an older series, official downloads may no longer be listed on the main Toshiba support site. You can typically find these files through the following community-driven platforms:
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 . Download TOSHIBA 40L5400ZE Firmware part4 rar
Turn off the TV, plug in the USB, and turn the TV back on. Some models will auto-detect the update. Because this specific model (40L5400ZE) is part of
Format a USB drive to FAT32 and copy the extracted file to the root directory (not inside a folder). Update Process: plug in the USB