Linux users can use hdparm --fwdownload to flash firmware. However, you need to extract the binary from Toshiba’s .exe (which often contains a bootable image). This is error-prone and not recommended for average users. It is not the "best" tool due to complexity and risk.
Toshiba’s official support website → Internal Hard Drives → Select your Series → "Downloads" or "Firmware" tab. toshiba hdd firmware update tool best