Again, I do not see any such thing. Look at the sentence again:
"God foreknows the future because God foreordained the future."
That could also be said this way with no change in meaning:
God foreordained the future, therefore He foreknows the future.
To say that foreknowledge is dependent on omnipotence can be reduced to saying that knowledge is dependent on power, when the old saying is that Knowledge IS Power. Can you truly say that if one is powerless, that they are therefore without knowledge? Or that If they have no knowledge, they therefore necessarily have no power? I don't see that either of those comparisons can be called truisms. The one does not follow from the other. A logical fallacy, if you will; A false causality. You're trying to draw a parallel where none exists.
That is exactly my concern. You see the logic of what I am worried about. Just because one is powerless does not mean that they are without knowledge.
The following 3 excerpts from Boettner do not seem to agree with either of us.
Scripture teaches very explicitly that God acts according to a plan And, knowing that plan, he knows the future.
His decrees therefore are eternal, unchangeable, holy, wise, and sovereign. They are represented as being the basis of the divine foreknowledge (q.v.) of all future events, and not conditioned by that knowledge or by anything originated by the events themselves.
...our fore knowledge does not precede determination, but follows it and is based upon it. God foreknows the future because he has foreordained the future. (Boettner, Wycliffe, "Predestination.")
This says three things: (1) that the decrees are THE BASIS of the divine foreknowledge. (2) It says that God has a plan, and that His knowledge of the plan leads to his knowing the future. (3) This says that God know the future BECAUSE he has foreordained the future.
Divine foreknowledge is based on Decrees.
Divine foreknowledge is based on God's knowledge of His Plan.
Divine foreknowledge is based on God's foreordinaton of the future.
Use those 3 points as the factual information on which you MUST BASE the answer to your question above: "Can you truly say that if GOD is powerless, that GOD IS therefore without knowledge?"
Using the facts presented by Boettner, I MUST conclude that if God were powerless that God could not have knowledge of the Future.