pls help!H1B transfer, does it need employer sponsorship?

I am a H1B holder and filing I485 in EB2. My I485 is pending over 180 days and PD is current now. I am applying for a new job. The new employer said they don't sponsor Green card.

I wonder:
1. Do I need anything from employer to transfer H1B? My thinking is if I don't need anything from the new employer to transfer H1B, I can get my own lawyer to do it.

2. I have used AP to go back China. But never used EAD. Someone said once I used AP, my H1B is already invalid. I read pijiang's article that as long as I don't use EAD, I still can transfer H1B. Anyone can confirm this?

Thanks much!