OpenWrt installation on FRITZ!WLAN Repeater 1750E

Hello, I have a problem installing openwrt on FRITZ!WLAN Repeater 1750E. Can you help me with this? I have the installation procedure at:

tracked, but I can not access via PDF command: ftp -pnvd on the Fritz, because I keep getting the same error: ftp: connect: connection refused. I've tried and checked everything possible and unfortunately I can't get any further. I would be very grateful for your support

from https://git.openwrt.org/?p=openwrt/openwrt.git;a=commit;h=8918c038f330a1bb5a898d80c170caf9f42cac89

In the first seconds after Power is connected, the bootloader will
listen for FTP connections on 192.168.178.1.

Are you quick enough with issuing the ftp command?

how do you mean it..? I connected the Fritz to my switch. Assign an IP address beforehand: 192.168.1.122 and then enter the commands via my Laptop Linux Deepin terminal.

Is ping working to the fritzbox as in are you sure the ip-address is correct for the bootloader in tftp mode?

In my situation (FB6490) the bootloader IP was different eventhough the router was factory reseted!

Try opening the hidden support page in your current fritzbox http://fritzboxip/support.lua it may ask 2 times for password login and download the (advanced) Support Information which actually takes more than a minute.

In this document you may find a other IP-address for bootloader than default 192.168.178.1?

Hello, I thank you for your hints. Unfortunately I was away for a few days and couldn't do anything. I'll let you know as soon as I can try something. Thank you very much