Always use your software to "Read" and save the current firmware before overwriting it.
: Locate the .hex (Flash) and .eep (EEPROM) files from your downloaded folder that match your hardware (typically Mega328p at 16MHz for a standard T7).
Before downloading, you must identify the chip inside your T7. Open the case and check the marking on the IC: The standard for newer T7/T7-H models. ATmega644: Often found in upgraded versions. ATmega1284: Found in high-end DIY versions.
Use the command line or a GUI like AVRDUDESS to upload the .hex (flash) and .eep (EEPROM) files.