Can't push_firmware to fritzbox 7390

[HostXnine]

Hello guys I've have some trouble with pushing my firmware to the FritzBox fon wlan 7390. I successfully build an image with external files because if I don't do it that way it's too big. I've saved the external file on the Fritzbox as I suppose I should.

I've tried it several times with different settings options. Also resetting the box to factory settings, no matter what I do I always get the same result.
I've also added my config file which I used to build my image.

Current FritzOS version 6.87
config.log

Thank you in advance for your help!

jan@jan-VirtualBox-mint:~/freetz-ng$ tools/push_firmware -ms -ip 192.168.8.40

 * Using command: ncftpput
 * Target host: 192.168.8.40
 * Outgoing IP: 192.168.8.106
 * Flash mode: single-boot

 !!! WARNING !!! WARNING !!! WARNING !!! WARNING !!! WARNING !!!
 !!!  THERE IS NO WARRANTY AT ALL !!! USE AT YOUR OWN RISK   !!!

 * Are you sure, that you want to flash this file to the device?
   images/7390_06.87.int_freetz-ng-21589-4c08dd921_20230520-223140.image
   Proceed? (y/[n]) y

 * You should now reboot your box (192.168.8.40). Waiting for shut down.
   Switch off, if reboot is not detected because it happens too quickly.
   Some newer bootloader versions allow to flash on power-cycle only.
   .................
 * No reply from box, assuming switch-off or restart. Trying to re-detect box.
   Waiting ...... found!

 * Box is back up again, initiating transfer.

LibNcFTP 3.2.5 (January 17, 2011) compiled for linux-x86_64-glibc2.31
Uname: Linux|jan-VirtualBox-mint|5.15.0-71-generic|#78-Ubuntu SMP Tue Apr 18 09:00:29 UTC 2023|x86_64
Contents of /etc/debian_version:
  bookworm/sid
Contents of /etc/issue:
  Linux Mint 21.1 Vera \n \l
  
Glibc: 2.35 (stable)
220: FRITZ!BoxFonWLAN7390 FTP server ready.
Connected to 192.168.8.40.
Cmd: USER adam2
230: User @SkipAuthFromHomenetwork logged in.
Logged in to 192.168.8.40 as adam2.
Cmd: MEDIA FLSH
500: 'MEDIA FLSH': command not understood.
Cmd: TYPE I
200: Type set to I.
Cmd: MLST mtd1
500: 'MLST mtd1': command not understood.
Cmd: PASV
227: Entering Passive Mode (192,168,8,40,176,55)
Cmd: STOR mtd1
150: Opening BINARY mode data connection for 'mtd1'.
/tmp/freetz_MUw:                   ETA:   0:03   12.81/ 14.15 MB  544.92 kB/s  226: Transfer complete.
/tmp/freetz_MUw:                                        14.15 MB  580.42 kB/s  
Cmd: REBOOT
500: 'REBOOT': command not understood.
Cmd: QUIT
221: Goodbye.

done
jan@jan-VirtualBox-mint:~/freetz-ng$

[fda77]

220: FRITZ!BoxFonWLAN7390 FTP server ready.

this is not the bootloader

[HostXnine]

Why not?
Is the config wrong?

[fda77]

-> https://www.ip-phone-forum.de/threads/315399/