for updating from dvr/nvr :

1:from device

copy firmware rom to fat32 flash drive ,extract the zip file and rename .bin file to update.bin

then go to version menu and click on “start” in upgrade section

2:network remote

download configtool software from dahua website

extract firmware zip file

search or add manually device in configtool

go to update menu

select previously extracted .bin file and wait for device to reboot