You can't efile 2024 or prior original or amended returns. But if the IRS didn't get your original return you don't amend it. Just fix the original return and mail it.
How did you amend it? Using the Online version or the Desktop program? To get back the original return you would have to open the amended return and delete the 1040X and take out any changes and put your return back to the original return. Then print and mail the original.
