Thank you so much for all this great work here. It took me several hours to go through it and finally get it to work.
My experience is that based on MacOS version, we need to
1. implement port limit removal patch so that we can see all the ports in IORegistryExplorer, I was on 10.14.3, so I use the patch for 10.14.2 provided in the forum. This is the most important step for me since I didn't have this in the first place. I directly identify the ports so short-cut which is a bad idea for my setup.
2. Identify the port, this will take some time but it's a fairly easy process, I have a total of 15ports for my H270m-d3h (I have a bluetooth/wifi card for airdrop purpose).
3. Generate SSDT_USB.aml , I modified mine so that port number are shown in hex value.
4. Reboot with the aml and everything is good.
I update to 10.14.5 and no issue at all, finally my external SSD can show it's full strength.
Thank you so much to RehabMan, UtterDisbelief and many others!