If I can modify ftp server to accept custom filenames ? Will I be able to flash the Digi with different name?

Can please explain me in details if changing the ftp server to accept different name other than image.bin will I be able to flash Digi module successfully.
Also let me know what the steps to be done if this is the only way to use customizable names.

Look inside your_DigiESPProject\sys\util\firmware.c
search for rom.bin, should give you what you need