What happens if your 6-year limit on H-1 visa expires during adjustment of status?

Once you apply for AoS, your status is considered as "applicant for adjustment of status." You can remain in the US even after your 6-year limit has expired until the I-485 process is completed. If you have not applied for AoS and your 6-year limit is reached, then you must apply for 1-year or 3-year extension of H-1 visa. Whether you are qualified to apply for H-1 extension will depend on the status of your employment-based green card application.