For testing purpose i have an old Fritz!Box 7360 flashed with OpenWRT. For $reasons I needed to reflash the original firmware. Unfortunaly the Recovery tool didn’t work with my model, because it used to be provider branded by EWE. There is a rebranded Version of the tool by EWE, but this didn’t work either.

So i researched a little and it turns out you can flash the firmware manually via the ADAM bootloader, just like OpenWRT.

  1. Download from ftp.avm.de (Or in my case download.ewe.de) the firmware suitable for your model.

  2. The .image file is a POSIX tar file, extract it via tar xfv *.image

  3. There should be following folder structure. The file kernel.image is what we need.

    ./var/
./var/flash_update_2.6.28.ko
./var/regelex
./var/install
./var/info.txt
./var/tmp/
./var/tmp/filesystem.image
./var/tmp/kernel.image
./var/flash_update_2.6.32.ko
./var/chksum
./var/signature

  4. Configure your interface to a fixed IP in the 192.168.178.0/24 network, e.g. 192.168.178.2/24

  5. Disconnect the FritzBox from the mains.

  6. Connect only your computer to the router.

  7. Open a terminal and type ftp -n -v -p 192.168.178.1 (without enter)

  8. Connect your router to the mains, and try to connect to the FTP server. It may take you several trials and errors to catch the correct time-frame.

  9. Flash the firmware via ftp:

    jan@jantop ~ % ftp -n -v -p 192.168.178.1
Connected to 192.168.178.1.
220 ADAM2 FTP Server ready
ftp> quote USER adam2
331 Password required for adam2
ftp> quote PASS adam2
230 User adam2 successfully logged in
ftp> quote MEDIA FLSH
200 Media set to MEDIA_FLASH
ftp> binary
200 Type set to BINARY
ftp> put kernel.image mtd1
227 Entering Passive Mode (192,168,178,1,12,10)
150 Opening BINARY data connection
226 Transfer complete
15914250 bytes sent in 32.6 seconds (476 kbytes/s)
ftp> quote REBOOT

  10. The router should now boot into the new firmware.