How will my H4 EAD be affected by spouse's H1b+i140 transfer

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My husband’s i140 got approved in 2017. He got his H1 extension approval in Sep 2018 and it expires in Sep 2021. I am on H4 visa and recently applied for my EAD card. Got approved and valid till Sep 2021. Now my husband has to change his job. I would like to know how this affects my H4 visa and EAD card.

• Once his H1 is transferred, will my H4 visa still be valid?
• Is my EAD card still valid during the H1 transfer period? Can I continue working?
• If his i140 gets transferred, will my EAD still be valid? Do I need to apply for a new EAD card?