Let me get this straight:
1. BM & PMiOS worked together on the 3GS
2. BM & PMiOS DON'T work together on the 4S
What iOS is on the 3GS and on the 4S?
If the same versions of BM & PMiOS that worked on the 3GS aren't working on the 4S, it is possibly an iOS setting.
User of Jefferson Bible, MPG, PMD, & PMiOS. Oh, and WeatherStick.