Here is the #1 reason uLaunchELF refuses to list your files:

Try a smaller, older, or simpler USB 2.0 flash drive.

Set the allocation unit size (cluster size) to (or 16 KB for drives under 8 GB). Execute the format. Step 2: Verify File and Folder Structure

If the drive is formatted correctly but still shows as empty:

Wait up to 10 seconds. The USB activity light (if your drive has one) should flash, and your files will populate the screen.

Sometimes uLaunchELF fails, but Open PS2 Loader (OPL) can read the drive.