Fritzbox 7520 Typ B

For Developers
1

Hi,

has anyone tried to get OpenWRT incl. DSL working on Fritzbox 7520 Typ B?

The wiki seems to indicate that the OpenWRT image for 7520 non-"Typ B" works, except for the DSL modem. Can someone confirm this?

How can I find out which DSL modem is built in? I dont have shell access, and I can't see the boot log. Do I need serial access, or is there any other way?

The open source files from the OEM have a DTS file, but I dont see anything DSL related in there: ./sources/kernel/linux/arch/arm/boot/dts/Fritz_Box_HW276-0.dts

Thank you for your support.

2

There is a forum thread on "Typ B" with the different modem which appears to confirm this. It ends with:

According to comments on the ip-phone-forum the Typ B is the only AVM product using this modem. (maybe due to a supply chain issue)
So the work can not be shared with other devices. As the 7520 can be had used for EUR 20-25, incl. shipping, all the time (just got some and look out for the price) I'd consider just getting a supported one and sell this one.
If you keep it you could get some good photos from the PCB and put them on the wiki.

1 Like
3

Hi, thank you for the very quick reply!

I will update the wiki with the information that you shared.

I bought the router by mistake and was hoping there was an easy fix…

I cant take pictures of the PCB since I dont have the appropriate screw driver. Maybe I can get one just for that

Best regards

4

A picture in the OpenWrt wiki would be nice, of course.

But if you are just curious about the internals, boxmatrix.info already has images. Unfortunately, the site is often broken due to database issues recently.

But the page content has been archived on the Wayback Machine: https://web.archive.org/web/20241202085827/https://boxmatrix.info/wiki/FRITZ!Box_7520_v2

And the actual images still seem to be up on the original server (if you ignore the expired TLS certificate):
https://boxmatrix.info/w/images/e/e0/FRITZ!Box_7520_v2-Image20.jpg
https://boxmatrix.info/w/images/e/e8/FRITZ!Box_7520_v2-Image18.jpg