I just did 3 wii's yesterday, 2 were already on 4.2 and I got DSI errors every time with YAWM, however one console came with 4.1 and the 4.2 upgrade worked perfect and then 4.2 mod worked perfect no DSI error.
Don't know if that helps, but for consoles that are on 4.2 i'm using MMM for now and...