i) It's often said that you can't use the Bible to prove the Bible. Unless the Bible is true, you can't use it to prove its veracity, since that's the very issue in dispute!
ii) Sounds plausible, but is it that simple? For instance, reviewers praise some memoirs if the autobiographer was candid about his foibles and misjudgments. His transparency is mark of veracity. What would motivate him to say unflattering things about himself unless he was honest?
That dovetails with the criterion of embarrassment. The Bible is chockfull of examples like that.
iii) But let's approach this from another angle. I think the apparent vicious circularity of using the Bible to prove the Bible is largely semantic. How can you use the same book to prove itself?
But that's deceptive. Although "the Bible" is a singular designation, it's actually an anthology of various writings by various writers.
Suppose an editor compiled a history of WWII by soliciting accounts from Churchill, Dwight Eisenhower, Curtis LeMay, Douglas MacArthur, George Marshall, George Patten, Chester Nimitz, and Matthew Ridgeway. Could you use his history to prove his history? Sure. Although it would technically be one book, it's actually a collection of independent accounts by leading participants. To a large degree, their respective accounts would be mutually corroborative.
You can do the same thing with the Bible. It's complicated, but there's nothing fallacious about the procedure.