If yours only has one header, you may be able to try to use a splitter cable, although it may be too much current required.
My mainboard has 2 5V ARGB headers, so I could probably connect each to one. I don't have the Uni-Fan controllers' ARGB connected to the mainboard at all, just controlling them via L-Connect 2 software. I'm using an NZXT Internal USB Hub 5-Port USB 2.0 Expansion myself. It depends how many internal USB headers you have on your motherboard. Wihile I'm not the original poster, I'm running two Uni Fan Hubs with L-Connect 2 now as well and will try to answer some of your questions: Good thing I ordered enough UF_EX cables. The only thing I noticed is that I had to keep the Strimer controller connected to a single port on the Uni Fan Hub on it's own, if I connected it together with any other ARGB device, the Strimers' LEDs would flicker (all of the other RGB devices are alright with being connected to one Uni Fan Hub Port in pairs). I updated each Hub (both are the old variant without the "SL" on it) connected one by one to the newly released Firmware and installed the newly released L-Connect 2 Software, it went without a hitch and it's working like a charm. Update: Thanks again to everyone for all the information! I decided to get another Uni Fan Hub and two sets of UF_EX Adapter cables and have now connected (almost) all my ARGB devices (10x Uni Fan SL120, 3x Uni Fan SL140, O11D G1 Distro Plate, O11D XL front side LED Strip, Strimer Plus 24 pin and Triple 8 pin, CPU Block, GPU Block) to the two Uni Fan Hubs. Before I go and potentially waste money on another 3-pack of Uni Fans, can anybody test/confirm this will actually work? Sadly I only bought one three pack and the rest single fans so I don't have a second controller to test with. I found a thread from 8 months ago where a Lian Li representative said they are working on it and it should be coming soon, but I'm not sure if that ever happened - one would think that in 8 months they would have figured it out, though. Now I'd like to add another three pack of fans for a Push/Pull configuration on my bottom radiator and would like to know if the L-Connect Software can control two (or more) Uni Fan Controllers at the same time (at least for RGB LEDs). This means my single fan controller is maxed out. I currently have 10 Lian-Li Uni Fan SL120 in my O11 Dynamic XL case (4 fan groups - 3 on the top radiator, 3 on the bottom radiator, 3 in the front and one on the back).