I strongly doubt about that!

Using EAD will invalide your H1B status. Thus once you use your EAD even for a small part time job, your status become pending. Thus you can not use your former H1 status to work for your H1 employer any more. As a result, you have to fill certain form to your employer to change your H1B to EAD.

If you said is true, then every one can open a business or find a second job with the EAD without invalidating their H1B, but this is far from what we have seen.