In the course of adding rebranding support to the Mate 10 Pro/Porsche US editions as part of FunkyHuawei (Please see this post for details: https://forum.xda-developers.com/sho...&postcount=711 ) I can confirm the following:1. The Mate 10 Pro and Porsche for sale in the US are re-purposed AT&T BLA-A09 devices. Other countries have the BLA-L29 or BLA-L09 so this is a US-centric codename, but in fact the hardware is identical.2. The US edition of the Mate 10 Pro is single-sim. The Mate 10 Pro Porsche for the US market is also single-sim (other markets had dual sim porsche design editions). This is because they originally intended to release the phone with AT&T, which obviously wouldn't want them to release a dual-sim phone. If you live in the US and want dual sim, you're better off buying an international model and rebranding it, so you can have the dual sim functionality.3. The US edition of the Mate 10 Pro/Porsche (or devices rebranded to the US branding) will support VoLTE on T-Mobile, but not VoWifi. However it does support both VoLTE and VoWifi on AT&T. If you want to check what is supported for your own MCC/MNC please look at this list, it's pulled from the US firmware:If anyone wants to know more, you can ask in this thread or in the FunkyHuawei thread. We'll probably have many users rebranding to it and using it in the US soon.