thota,
the following info is copied from other website. just for ur reference. contact your lawyer.
EAD for I-140/I-485 Concurrent filing
There are several specific rules that apply for issuance of EAD for those who file concurrent I-140/I-485 applications.
1.An applicant can apply for an EAD either along with I-485 application or any time after that as long as I-485 application is pending. If EAD is not issued by USCIS service center within 90 days, an applicant can obtain intermin EAD at local district office.
2.90 day clock stops ticking when the service center issues RFE for initial evidence with reference to the underlying I-140.When the requested initial evidence is received by the service center, 90 day clock starts to run all over again. Previously suspended time does not count in counting new 90 days.
3.EAD is issued "valid from the date of decision" and does not retroactively go back to the expiration date of the current EAD, if you are renewing EAD. If there is a gap between two EADs, and if the applicant works during that period, that would be considered as an unauthorized employment.
Keeping above rules in mind, it is advisable to file EAD along with filing I-485 application, even if you have valid/unexpired H1/L1 visa. Just getting an EAD does not put you in EAD status, but using it does. Please look at EAD/AP vs. H1 for more information. In case the person is laid off and in case the person is eligible for AC 21 and new employer is willing to do AC 21, but not willing to file new H1 petition, EAD would be very useful. In case the person reaches 6 years limit on H1B, in that case also, EAD would be very useful.