This page answers some Frequently Asked Questions about Freetz. It is still under construction.

Be aware that there is a more complete FAQ version in German.

Project name and history

What is Freetz?

Freetz is a toolbox for developers and experienced users to build a modified firmware based on the original firmware for the DSL/LAN/WLAN/VoIP-Routers AVM Fritz!Box and T-Com Speedport (identical hardware) and to transfer this firmware to the device. There are many extension packages available, along with options to remove unwanted functionality from the original firmware.

Where does the name Freetz come from?

It is a contraction of the word “free” and the name “Fritz”, intended to mirror the name of the devices manufactured by AVM . With this, we want to symbolise that Freetz is free software. In order to avoid intellectual property problems with AVM, whose registered trademark “Fritz!” (with exclamation mark) we explicitly acknowledge, we have chosen this deliberately different spelling. The idea for the name came from Alexander Kriegisch (kriegaex), who decided together with Oliver Metz (olistudent) what the project should be called when the version-managed source code repository would be opened to the public. From the (in our opinion daft-sounding) alliteration “Free Fritz” we got “Freetz”. (“OpenFritz “ was also considered, but we didn’t want to ape OpenWrt .) We don’t claim that the name is fantastic, but it is short and hopefully easy to remember. :-)

How should I pronounce Freetz?

Like the English word “free” with a German-sounding “tz” on the end, something like “freets”.

How did Freetz start?

There are many predecessors to Freetz . A few years ago, Daniel Eiband (danisahne) started the Danisahne-Mod ( DS-Mod ) based on the previous work and cooperation of other creative people (Erik Andersen, Christian Volkmann, Andreas Bühmann, Enrik Berkhan and others). As with Freetz , this allowed and allows modified firmwares to be created, but only for older firmware-versions with Linux kernel 2.4. Since some routers still have firmwares based on the Linux 2.4 kernel, the version ds-0.2.9-p8 is still the current version for some hardware. For the majority of current hardware, the immediate predecessor of Freetz is, however, ds26 (latest version ds26-15.2 ), created by Oliver Metz, which is only suitable for firmware using Linux kernel 2.6. The same applies to Freetz as Freetz is currently nothing other than the current development version of ds26 with a new name. In many files you will therefore still find the name DS-Mod , which will gradually be replaced with the new name Freetz .

Why change the name when DS-Mod has already become well-known?

There are multiple reasons. For one, Daniel has not been actively involved in the development of ds26 for well over a year. For another, he has already started a new project at SourceForge to develop a new DS-Mod from scratch - which we inoffically call DS-Mod NG (Next Generation) - for which the source code repository is publicly available on his project website . We don’t wish to take Daniel’s project name from him, or to compete with him, but actually hope that he will eventually have more time for his project and that we will be able to combine both versions to have the strengths of both of them in one product. However, at this point in time, the projects have split significantly; DS-Mod NG has a very clean structure, but is not yet finished whereas Freetz (previously ds26 ) is already widely used and is gradually being refactored during the process of development. Where DS-Mod was talked about in recent press coverage (e.g. PC-Welt ), Freetz alias ds26 was meant.

Why is so much of Freetz and the development in German?

AVM is a German company, and their hardware is mainly sold on the German market, where it is very popular and generally the German-language (and German telecoms-system) versions of their products are the first to be released. It is therefore not surprising that the project started in Germany and most of the developers are German. There are some current ideas of how to better integrate internationalization support, and although most development discussions take place in German, contributions in English are most welcome (and will usually be answered in English).


Why change the firmware?

It is possible to edit some special files (character devices) under /var/flash where the contents still exist after reboot, but this is not true for the rest of the filesystem. The content of these character devices is located in its own rather tiny flash partition. Most data is stored on a read-only SquashFS filesystem which can only be modified during a firmware update, using a SquashFS filesystem image. To permanently include (larger) files into the firmware, they must be put into the SqashFS image, which is implemented in Freetz.


Can I get a finished binary of Freetz?

The short answer is no, and this is never likely to be possible. Freetz works by taking the original firmware and applying patches to it. Since the original firmwares contain software which is non-free, as well as some which is free, that means we are not able to distribute finished binary versions. Also, given the number of permutations of modules and hardware then it would be impossible to meet all needs with a limited number of binaries and so it is actually of advantage to have users build their own firmware, tailored to their individual needs.

How can I get Freetz?

See the Getting Started page for how to check out the source code and get started with Freetz . Note that this requires a working Linux installation (a Live-CD or Virtual Machine version will do if you do not want to fully install Linux on your computer). Please make sure that you have basic Linux skills before requesting help as this will make your, and our, lives easier.

Which type of boxes and which firmware versions are currently supported?:


When will version xy be released?

Generally speaking: It’s done when it’s done. The developers are working in their off time, new releases are provided if the decided-on features are completed and critical bugs were fixed.

Still, a rough plan for new releases does exist: 3-4 months after a stable release we declare a “Feature-Freeze” for the following release. From that time on, only bugs are being fixed. The feature-freeze dates are announced in the roadmap . After the feature-freeze you can expect the final release to be released in about 1 to 1,5 months. Between the stable feature-releases there can be some maintenance-releases provided to support newer firmware versions by AVM or some error-fixes.

Trunk, Branches, Tags?

The trunk is the current development tree. A branch is a tree which is separated from the trunk at a specific time (e.g. Changeset r2759). All release versions are tagged

To check out current development version:

git clone https://github.com/Freetz-NG/freetz-ng ~/freetz-ng

When feature XY is implemented?

The fastest way is to present an working solution. We take notice of every reasonable feature request. Due to the developers designing Freetz in their off time, you have to be patient sometimes.

I like Freetz and I want to support the development.

It is possible to donate money to the development team using the PayPal donation button at the bottom right-hand corner. Further, a specific hardware variation will of course be better supported when the development team has some test hardware. Currently we would very much benefit from some 7270s (who wouldn’t?!). There is a thread on the topic of donations at IPPF .

Pre-Configuration (menuconfig)

Do I have the 8MB (v1) or 16MB (v2) version of the FB 7270?

1.) read the support file at http://fritz.box/html/support.html
2.) The file should contain the following entry:\

00800000 Hex = 8.388.608 decimal = 8.192 KB = 8 MB
01000000 Hex = 16.777.216 decimal = 16.384 KB = 16 MB\

More details are described [here].

What are indicators for a FB 7270v3?

Which packages should be built into a Freetz image?

We recommend Dropbear to have SSH access, as well as dnsmasq as DHCP server replacement.

What does “binary only” mean?

Packages tagged with “binary only” do not supply any web frontend, init script or anything similar. They provide only the binaries themselves, which means you have to take care of the configuration, initialization etc. yourself. (Note: Other than the name (maybe) suggests, these packages are - along with every other package in Freetz - built from source.)

Image Build (make/build)

Meaning of the specific make-targets

A: The make-targets are influencing the build process and creating the firmware. Most of the following information was taken from this thread originally.

1. Clean-Up:

2. Preparations:

Building another firmware language

The firmware language/version should match your box type, else your box will go into a reboot loop.

Check the advanced option Enforce urlader environment and put avm in Patches > Enforce firmware_version variable to build [German]{.underline} firmware for an [international]{.underline} box. If you want to do this (or the other way around with avme for [English]{.underline} firmware on a [non-international]{.underline} box), read about recovery and have a working/recovery image ready.

Problems during building

If you encounter problems during the build process, go through this list first:

You must have either have gettext support in your C library, or use the GNU gettext library.

There is a wrong value in config.cache. Delete the file by typing: “rm make/config.cache” or “rm source/target-mipsel_uClibc- 0.X.XX /config.cache”

ERROR: The program/library/header xy was not found…

If the build process was interrupted by this message, some necessary packages for the build system are missing. Please install them and restart the build process.

WARNING: The program/library/header xy was not found…

If the build process was interrupted by this message, maybe some packages providing the needed library are missing. This can be caused by selecting some options or packages in menuconfig. Please install the needed libraries by installing the packages and restart the build process.

No such file `FRITZ.Box_xxxxxxxxx.aa.bb.cc.image’

This happens every time AVM releases a new firmware version. Normally only the newest file is available on the AVM FTP server. Freetz can only support the version that’s current at the release date. Due to license restrictions, we cannot provide these images. Possible solutions (prioritized by difficulty):

Please use the last 2 possibilities at your own risk. If it’s just a “bugfix release” (like the update from .57 to .59) it should work without errors. However, if major changes were done by AVM at the latest firmware release, use it carefully!!

Please copy the following file into the ‘dl/fw’ sub-directory manually: fritz_box_aa_bb_cc-ddddd.image

The beta firmwares (Labor-Firmware) cannot be downloaded from the AVM-FTP-Server. Please download them manually from the AVM-Labor-Site . You must agree the license terms to get the file. After finishing download, put all files into the ‘dl/fw’ directory. Please also consider the headpoint before.

./ln: cannot execute binary file

The current working directory ‘.’ is within the path (variable PATH). To make a successfully build, the directory must be removed.

Filesystem image too big

The firmware image doesn’t fit into the flash memory of the selected box.

WARNING: Not enough free flash space for answering machine!

The image is small enough to fit on flash memory, but you have not enough free space left for the answering machine, or non space left. The firmare should work in spite of this message, but to ensure a fully functional answering machine or fax service, you should use an FAT-formatted USB-Stick to use this space for the answering machine, fax service and other services.

Background Information: Since a few firmware versions, AVM tries to use the remaining bytes in the Flash to create an jffs2-Partition. In this partition all data for e.g. the answering machine, fax service and so on are stored. On older boxes (e.g. 7170) the jffs2-Partition cannot be created as space howsoever is very limited. Please see this message as an warning. More informations at the IPPF-Thread . In FREETZ available since revision Changeset r3049 .

The problem still occurs. What now?

At first go into the ‘Advanced Options’ of menuconfig, change the ‘Verbosity Level’ to 2 and execute make again. After that go to the IPPF Forum and search for the error message or for an existing thread. If nothing could be found, create a new thread to get help with the given error message (please post it inside Code-Tags), the file .config (your configuration as attachment) and the used version or SVN branch/-revision.

Flashing of Compiled Image

Problems after (successful) Flashing

Settings are not available at current security level

There are several security levels. The level can be changed using the following commands:

   echo x > /tmp/flash/security ( after r3318: echo x > /tmp/flash/mod/security)

 * with x being one of the following values:
 * 0 : no restrictions
 * 1 : only configuration files without shell commands (shell scripts) can be modified
 * 2 : no configuration files can be modified

What is the default password for freetz?

The default password for freetz (both for console and web login) is “freetz”. Login name for console is “root”, and for the web interface it is admin. When you first log in using telnet or ssh, you have to change your password.

See this thread.


Were is the whole configuration stored on the Fritzbox?

The whole configuration on the Fritzbox can be found under /tmp/flash. This is important if you build a Freetz firmware, because the configuration is not located in the static firmware part of the image. All files located under /tmp/flash were not be edited during a firmware update, so the configuration files will be keeped after a firmware update. Important, always execute “modsave” after making changes on the configuration files under /tmp/flash, to save them in the flash. More information about that see below.

Configuration not available at the current security level!

There are different security levels. Depending on the selected level, not all configuration files are editable.

echo x > /tmp/flash/security (since r3318: echo x > /tmp/flash/mod/security)
# with x being one of the following values:
# 0 : no restrictions
# 1 : only configuration files without shell commands (shell scripts) can be modified
# 2 : no configuration files can be modified

This must be done after installing the new firmware on the Box via Telnet or SSH (not possible over the Rudi-Shell, because it also requires security level “0”).

How can i disable the password for the Freetz-Website?

Execute the following command on the terminal:

touch /tmp/flash/webcfg_conf
chmod +x /tmp/flash/webcfg_conf
modsave flash
/etc/init.d/rc.webcfg restart

Background: The script /tmp/flash/webcfg_conf will be preferred compared to /etc/default.webcfg/webcfg_conf to create the configuration file. An empty script /tmp/flash/webcfg_conf will create an empty configuration file without a password.

How can i change the password for the Freetz-Website?

This can be done via the web interface by itself: http://fritz.box:81/cgi-bin/passwd.cgi

How can i reset the password for the Freetz-Website in case I’ve lost it but still have access via telnet/SSH?

At first, stop the Freetz-Webif:

/etc/init.d/rc.webcfg stop

Then use vi to open the file mod.cfg and edit the line that begins with “export MOD_HTTPD_PASSWD” as follows:

vi /var/mod/etc/conf/mod.cfg
export MOD_HTTPD_PASSWD='$1$$zO6d3zi9DefdWLMB.OHaO.'

Now start the Freetz-Web interface:

/etc/init.d/rc.webcfg start

Now you can log in to the Web interface with the password “freetz”.

Please consider, that this change will NOT persist across reboots. So after a reboot, you still have the old unknown password. Therefore, you should change the password of the Box in the freetz-menu under Settings before you reboot your Fritzbox.

How can I change the root-Password?

Execute the following commands on the terminal:

modusers save
modsave flash

After entering ‘passwd’ you must type in the password. While typing, the password will ‘not’ be shown. Too simple passwords will not be accepted.

Problems During Working

/var/flash/freetz too big

The default limit set by Freetz for the maximum size of the configuration was exceeded. This limit is a protection to prevent an unintended full TFFS. This limit can be increased, but you should keep an eye on the current fill level:

modconf set mod MOD_LIMIT=<bytes>
modconf save mod
modsave flash

No ftp access after Freetz

This is a problem which occurs especially in Freetz 1.1.x. More details and solution can be found in the howto .

Removing FREETZ and Other Modifications


How can I use an own/other DNS server for all connected PCs and Fritzbox?

AVM doesn’t allow the modification of the default DNS servers the Box is using, instead of other routers which can change it via the WebUI. (End of 2009).

Possible Solutions:

How can I create character devices?

Freetz uses also a character device, which can save files enduring with help of a Tiny Flash Filesystems (TFFS) in the Flash, to save the configuration. Prerequisite is a minor number, which is not used by any other character device under /var/flash/ (Freetz uses the minor 0x3c), the major number can be read from /proc/devices:

mknod /var/flash/<name-of-file> c <major> <minor>

Because this character device is created in a ramdisk under /var/, this command must be executed every time during a restart. The content is achieving.

The current fill level can be shown like this:

    echo 'cleanup' > /proc/tffs

    echo 'info' > /proc/tffs

    cat /proc/tffs | grep '^fill='

Which network cable is necessary for a recover?

RJ45 standard network cable, no crossover

How old is my FritzBox?

The first four characters of the box’ serial number describe its age:\

Example: W484-xxx-xx-xxx-xxx ⇒ Thursday, 27.11.2008\

U = 2006
V = 2007
W = 2008
X = 2009
A = 2010\

W451 = calendar week 45 and the first day of that week = Monday
W462 = calendar week 46 and the second day of that week = Tuesday
W473 = calendar week 47 and the third day of that week = Wednesday
W484 = calendar week 48 and the fourth day of that week = Thursday
W495 = calendar week 49 the fifth day of that week = Friday\

How much RAM does my FritzBox contain?

For the second xxxx-XXX-xxx-xxx currently, the following codes are known to occur:\

Example: W484-305-xx-xxx-xxx ⇒ Fritzbox with 16MB and 1und1 branding\

293 - HWRev 122 (8MB/7270_V1) - AVM branding
294 - HWRev 122 (8MB/7270_V1) - 1und1 branding
304 - HWRev 139 (16MB/7270_V2) - AVM branding
305 - HWRev 139 (16MB/7270_V2) - 1und1 branding
xxx - HWRev 145 (16MB/7270_V3) - ??? branding - 7270_V3
307 - HWRev 139 (16MB/7270_V2) - AVME branding International Version?
310 - HWRev 139 (16MB/7270_V2) - AVME branding A-/CH-Version?\