After working on the FRITZ!Box 3390, I started porting OpenWrt to the FRITZ!Box 3490. So far, it seems very similar to the 3390 and most tools work with no or just a few modifications.
It follows a design very similar to the 3390, but is more powerful:
- Lantiq target with 256MB RAM and 512MiB NAND
- ath79 target with 128MB RAM and WiFi modules (2.4GHz and 5GHz are most likely both connected to the ath79)
The communication between the two SoC is similar (i.e. stage 1 loader via MDIO, stage 2 firmware via raw ethernet frames), but I need to figure out a few more commands for the MDIO upload - so far, the stage 1 loader is transferred, but does not start.
The good news is that I finally figured out the checksumming algorithm and can now upload any loader via MDIO.
The bad news is that the Lantiq target requires a few more patches to work properly:
- The NAND is only supported in 4.20, luckily, I found a backport-patch
- The xhci controller requires a firmware upload, luckily, I found a patch in the apm821xx target
Once I've figured the remaining parts out, I'll try to get it officially supported - at least, the Lantiq target.