Hi, I have two of these devices, in EU version. The stock firmware on these is 3.15.3 Build 180305 Rel. 51282n
I have tried to flash the EU factory Firmware: http://downloads.openwrt.org/releases/18.06.4/targets/ar71xx/generic/openwrt-18.06.4-ar71xx-generic-archer-c7-v2-squashfs-factory-eu.bin - tried via webinterface as well as using TFTP.
However, after a reboot it is getting an IP address via DHCP if I connect it to my LAN, however it cannot be reached on this address. If not on DHCP, I believe it does not get the 192.168.1.1 (according to wireshark).
I also tried to first install DD-WRT but also this is nt starting and I have to recover then.
Thanks for your help!