Hey there!
Thank you for this firmware @juppin!
I have Archer c7 v4 already openwrt installed. I am using this as a main router and I suffer from the speed issue discussed before. I would like to try your firmware on my device but I see that there is no support available. I tried to sysupgrade with -F flag over my existing AR71xx installation, and I bricked my device. Luckily, I have enough power user capability to restore it via TFTP.
If you have your github repository for your project, I'd really like to access it to try to compile it for device. If it's not possible, could you please add support for Archer c7 v4 (AC1790)? I can try this firmware. Should something goes wrong, I can easily restore my firmware. I already have snapshot release with openwrt with 4.9.14 kernel.
Thank you!