OK since I figured it out, an UPDATE to this cause someone might need it:
My Owsoo has the Hi3520 chipset (both for 4 and 8 IP cams). The firmware is identical with this Sunywo brand. you can download version 1.0.1.6964 at 资源下载 - 尚维国际 by selecting NVR4 20161110-Xin Wei Hao -NVR4-V1.0.1.6964...