Many AVM devices can be unbricked by a AVM recovery tool which is specific to your device.
Example: For Fritz!Box 7530 https://download.avm.de/fritzbox/fritzbox-7530/other/recover/
Search the corresponding recovery tool for your specific device on the AVM FTP server.
If you have a branded (e.g. 1&1) AVM device and you get the following message
The device contains basic settings adapted for your Internet Service Provider
when trying to go back to OEM firmware via the AVM recovery tool, you have to unbrand your device first. See the procedure below how to do this.
ftp -n 192.168.178.1<!-- -->
- Refer to the scripts in this thread: [[https://forum.openwrt.org/t/fritzbox-4040-flash-ftp-connection-refused/42543/4]].
- Run tha AVM recovery tool until the prompt appears that warns 'The device contains basic settings adapted for your Internet Service Provider'. At this point, leave the prompt open and the tool running, and the FTP connection should be possible.
- Once connected to the FTP server, issue the following set of commands:\\ <code>
quote USER adam2
quote PASS adam2
quote SETENV firmware_version avm
quote UNSETENV provider
quit
</code> Not sure if it's necessary to change the firmware_version variable.
The following steps worked for FRITZ!Box 7530 from Zen. A Windows machine is needed.
Afterwards, remember to clear the settings on your ethernet port, i.e., undo step 1 and 2.
Instructions by AVM themselves say that one error can be prevented by using only 10 Mbit/s half-duplex mode on the ethernet port. This supposedly avoids the "Could not determine the version!" error. ↩︎
The bootloader's FTP is not immediately available. As per above instructions, I ran the AVM tool first until it reached the 'The device contains basic settings adapted ...' state and left it like that. Then FTP was available. ↩︎
I skipped the ```quote SETENV firmware_version avm``` command. One of these alternations to the procedure helped me get past the "Could not determine the version!" error. ↩︎