unable to restore iPad 2 from iTunes

My iPad 2 is stuck in the Loop of Doom ... keeps trying to restart, but won't, infinitely trying. I connected to iTunes. Update wasn't an option, but it tried to restore. I've tried twice, and after each attempt, iTunes gives the error message "This iPad could not be restored. This device isn't eligible for the requested build." I assume it's too old for the restore sotftware iTunes is attempting? How can I restore an old model? I prefer an old iOS, so that's not a problem. thanks for your help!