I was having a lot of problems trying to get my USB microphones to work my Wii USB Loader ... I was using cIOS36 rev10 and Configurable USB Loader v37
I have just installed cIOS38 rev14 (no additional updates/patches required - I do not have Hermes 222/223 mload installed) and it looks like it has resolved the issue at least partially for me! ... I say partially because I have dual mics with a usb adapter but at the moment it only functions as a single mic ... both mics are not detected
I only have two games to test with at the moment ... "Guitar Hero: World Tour (PAL)" and "Disney Sing It High School Musical 3 (PAL)" ... Guitar Hero: World Tour looks like it is only designed to allow a single mic connection ... Disney Sing It High School Musical 3 has Dual Player modes and unfortunately I can only get/see one mic working!
I will be trying another set of dual mics with adapter in the next day or two so hopefully I can confirm whether the problem is with the particular dual mics I have or perhaps the firmware support for USB mics in cIOS38 rev14 may well still be buggy or incomplete ???