Ah ok..you buy into the oral tradition claim of Judaism?
I don't.
Somehow, the Jews of Josiah's day no longer had an understanding of the WRITTEN LAW, until a copy was found in the Temple. I don't believe there was an oral tradition alongside the written word..and if there was, it wouldn't mean much to me.
Scripture warns against paying attention to Jewish fables. I don't consider works such as Josephus' to be reliable, either. He was known to exaggerate, and I'm pretty sure other Jewish sources did the same thing.
I am Sola Scriptura man