As per murthy chat, your H1 goes to "sleep" if you use EAD to work for another employer, besides your current employer. If in future you decide to get back on H1, you can go out of country, apply for H1 visa and come back on H1 status (if still working for the H1 sponsoring employer). Needless to say, if you decide to use EAD at that point again, your H1 goes to sleep again. Also, if you do terminate employment with your H1 sponsoring employer, you loose H1 status irrespective of your use of EAD.