I don't know exactly who you are addressing, but: If you read through this thread, you get a more-or-less-complete guide on how to compile and install yourself. @DocMAX said he will prepare a step-by-step guide once he sorted everything out, so you might just have to wait a little.
Source Code: https://github.com/andyboeh/openwrt/tree/avm_fritz3490 and https://github.com/andyboeh/openwrt/tree/avm_fritz3490_wasp
Depending on your level of knowledge, I suggest the following as reads:
The WiFi part is only supported if you install additional patches, packages and compile a separate OpenWrt build for the WiFi hardware that runs from RAM. The pieces are generally there for the 3390 and the 3490, but you need to port them yourself to the 7490 (at least as far as I know).
Basically, you will need:
Lantiq target: https://github.com/andyboeh/openwrt/tree/avm_fritz3490 which has more patches applied than the 7490 PR. Port the patches to the 7490
ath79 WiFi target: https://github.…
A quote from one of the posts that I asked you to read:
Edit: To sum up:
ath_tgt_fw1.fw needs to go to /opt/wasp, not to /lib/firmware
ath_tgt_fw2.fw is not needed - this is replaced by the ath79 openwrt image
to start WiFi, you somehow need to load the ath79 image. This is done by running /opt/wasp/upload-wasp.sh
What we didn't discuss yet is how you configure WiFi: The ath79 target has no access to the flash memory, thus configuration within this target is not persistent. To overcome th…