The IRS has not processed any mailed returns of any type for many weeks. Mailed returns are sitting in stacks in trailers at regional processing centers waiting to be opened for processing by the IRS employees when they return to work. They have not said how long it will take to get caught up with mailed returns. In normal times, an amended return takes 16 weeks to process. It will likely take a lot longer now.
When they do start processing it, you can track the status using this web site: https://www.irs.gov/filing/wheres-my-amended-return
