@ZINGARO1972 Sure you can move files around in /tftpboot. That’s one way of doing it. Or you can use symbolic links. Or change the filename in your DHCP configuration. Moving files or using symbolic links you might overwrite files if you don’t pay full attention. So I’d prefer to change DHCP config.
I guess you installed FOG with DHCP. Then edit /etc/dhcp/dhcpd.conf and simply change the filename there. After saving the file you only need to restart the DHCP service: service isc-dhcp-server restart