按照移民局的要求，只要移民局受理了OPT延期的申请，就可以使用之前过期的EAD卡，配合OPT延期的receipt和I-20继续合法工作。移民局的官方说明：
If you file your STEM OPT extension application on time and your OPT period expires while your extension application is pending, we will automatically extend your employment authorization for 180 days. This automatic 180-day extension ceases once USCIS adjudicates your STEM OPT extension application.
The expired EAD with an endorsed Form I-20 is acceptable until USCIS makes a decision on the student’s application, but for not more than180 days from the date the student’s initial OPT EAD expires. Employment authorization must be reverified after 180 days from the date the EAD expires to continue employment.
