EIP 2 would have been automatically credited to you when you prepared your first return if you qualified, and you would have had to take a specific step to remove it. In order for the IRS to accept the amended return and pay an additional $600, you would have to be in a situation where you changed some other facts on your return to make you eligible, or you accidentally removed the credit when you filed the first time. So it's not clear you are actually eligible. More information might be helpful.
