Hi there, my new Ubuiquiti Litebeam 5AC Gen2 denies to be downgraded to OS v8.7.0 as described in the manual. It run on 8.7.11 build 46972 -> if I try to upload v8.7.0 I get an error saying "incorrect firmware version. Please upload v8.7.4 or newer". Now I've downgraded to v8.7.4 but still no luck to install v8.7.0 now. Any suggestions?