I485s pending -means you can stay as long as

ur 485 is not denied.
you can find a new employment, but must be in the same field and similar type of job that you got ur I-140.
If you did not have an interview or request for additional information, you may proceed to your LPR directly.
but if u are scheduled for an interview, MUST work. EAD can be used as long as I-485 is pending. the Pay could not be less than what's your I-140 or LC.

You can stay as long as your I-485 is pending.

Filing a I-485 gives your a status bewtween legal and illegal, untouchable by USCIS.
But if you lost your H-1 and I-485 is denied, EAD will be denied as well. you lose all.