Your H1 is invalid once you use EAD
Once you used EAD, for any kind of job, part time or full time, daytime or night time, supermarket or IT, your H-1 is invalid. You should inform the first employer (H1 sponsor) and let them do the admin. work. (It is not a great deal of work they need to do.) They don\'t need to inform the INS of the termination of H-1 or anything.
But be careful, if you are planning to leave the country during this period (485 pending). You will need AP to re-enter since your H-1 is invalid.