There are several ways to factory reset a Fritz!box router but unlike a lot of other embedded devices the reset button isn't one of them. You can however reset via the following techniques by following some generic instructions at the Fritz!box website: http://en.avm.de/service/fritzbox/fritzbox-7490/knowledge-base/publication/show/160_Restoring-the-FRITZ-OS-of-your-FRITZ-Box/
Current techniques include:
-
Web interface (requires admin access)
-
Analogue telephone (via key presses)
- Custom AVM
1. Web Interface (requires admin access)
If you know the current IP address and administrator password of the Fritz!Box then you can log in to the web interface and reset it to factory defaults from there.
Go to System > Backup, then select the Factory Settings tab. Click Load Factory Settings and OK.
Note: If you still know the password but not the current IP address of the Fritz!Box you can manually set your workstation IP address to be 169.254.1.20 with a subnet mask 255.255.0.0, and access the router at http://169.254.1.1 for web configuration.
2. Analogue Telephone (via key presses)
For the Fritz!Box and without a known IP address or admin password you can reset the unit with a standard analogue phone attached to the FON1 port of the Fritz!Box and dial #991*15901590*
3. Custom AVM - Last Resort
When all else fails sometimes your only option is to completely flatten any configuration. To do this you will need to download a custom update program from ftp.avm.de.
The recovery image you need to download is different for every platform and available from the AVM FTP service ftp://ftp.awm.de/frtix.box/fritzbox.[model#]/x_misc/english/[model-version].recover-image.exe
As of April 2016: