(High Sierra) USB Storage Devices Not Recognized

High Sierra (10.13.2) -- Hardware: https://pcpartpicker.com/list/wVQhCy

Problem: I plug in a totally working USB storage device (external disk) with a valid filesystem (ExFAT) and nothing happens. Nothing gets mounted, and system profiler under "USB" does not see that a disk has been plugged in.

• The external disk works on my non-Hackintosh machine;
• The external disk works on my Windows 10 gaming machine;
• The cable is fine;
• The same USB ports all recognize other devices (a webcam, my Nexus 6P, and a USB Hub);
• I've plugged it in directly to the computer without any hub device in the way (still not recognized);
• I've also tried going through the USB hub in hopes that might work, which doesn't.

What could I be doing wrong here? I've verified the disks, the cables, the ports, everything checks out except the operating system. It sees other USB devices, but not external storage whatsoever.

Here's my current config.plist -- https://pastebin.com/KFJJwZSR -- and a few notes on it:

1. Line 88, I've experimented with high current off and on, no effect;
2. Line 175-185, I've tried it both without IOAHCIBlockStorage replacement and with it, no effect either way.

Does anybody know how I can get this working? Thanks.