In instruction of I-485, "If your form I-485 is related to an employment-based visa petition (Form I-140), you must submit a letter on the letterhead of the petitioning employer which confirms that the job on which the visa petition is based is still available to you. The letter must also state the salary that will be paid"
My question
I am 100% sure: EB1A I-140 doesn't need any support from employers. (in the whole process of mine, I didn't talk about it with my employer except responding the kind concern)
For I-485,
(1) "the job ...is still available to you". Logically these words are not applicable to EB1A because the word "still". --- I judged, but not confident.
(2) Some friends said: employment letter is necessary. So I hope to see the substantial web-site or something to confirm.