When pushing firmware to AVM hardware using FTP (adam) the IP address to push to depends on the firmware(!?) actually installed on the FritzBox. E.g. when using Telekom hardware like the Speedport W920V you can use the original FritzBox 7570 firmware.
If the installed firmware is a Telekom firmware the IP address is 192.168.2.1
if it’s an AVM firmware it is 192.168.178.1