It's just usually not an issue, because it's working straight away with the Ultra. There have been initial issues for some when this feature was first introduced with the WiiM Amp, but by now it should be pretty much sorted.
You can access the content presented by the local MiniDLNA server in three different ways from the WiiM Home app:
- Device tab, settings gear icon, Audio Input, USB
- Browse tab, Home Music Share, <WiiM_Device_Name>:Media Server
- Browse tab, Select Source on <WiiM_Device_Name> -> USB
The third method requires the least amounts of taps, so I will just refer to this one from now on. The following screenshots are from a WiiM Amp, but the Ultra behaves exactly the same.
Prior to inserting the USB thumb drive the Select Source section will look something like this (plus more inputs available on the Ultra):
View attachment 9221
Note that USB is not present, yet. When you plug in the USB drive the selection should change within a few seconds to look similar to this:
View attachment 9222
Tap on USB. If the content of this particular drive has not been indexed before, the following screen will show up:
View attachment 9223
Hit Scan Now. Depending on the write speed of your USB drive the scanning process might take a while. The app warns you to keep it in the foreground until the scan has finished.
View attachment 9224
Eventually the scan will come to an end. Hit Let's Get Started.
View attachment 9225
The GUI will show up. The three dots menu in the top right corner contains an option to update the index.
View attachment 9226
From now on you can access the content of the USB drive like the content from any other DLNA server on your network. And you can also access it from any other device on your network that support DLNA sources.
The Select Source section on the Browse tab will display USB in bold letters, but Wi-Fi (or Ethernet) will remain marked with the tick. The Ultra does not access the contents of the thumb drive directly, but through the MiniDLNA server like any other DLNA server on the same network.
Good luck.