I had a discussion with one of my students this semester on free will, since I was teaching a class that explored the subject from many different perspectives. I wrote:
If we say,"I wore a blue shirt today, and God knew I would wear a blue shirt today," the problem is that God's knowledge becomes located in the past by means of the perfect tense "knew" and the subjunctive verb "would" (within this context) indicates that an event might potentially happen. So Boethius and Aquinas completely remove time from the equation which is admittedly difficult when all we have is human language, yet some languages may be tenseless or express concepts tenselessly with relative ease. Putting those issues aside for a moment, here's another problem.
1) God cannot hold a mistaken belief (premise based on divine omniscience)
2) At T1 (some point in the past), God believes that I will wear a blue shirt at T2.
3) Therefore, I will wear a blue shirt at T2.
The implication from this argument is that I cannot do otherwise than wear a blue shirt at T2. Now you may counter by arguing that God's knowledge at T1 did not cause me to wear a blue shirt at T2. Let's say that I grant your point; still, it's hard for me to see how I can do otherwise at T2 if God knows what I'm going to do at T1. If I do other than what God believes I would do at T2, then I thereby falsify God's belief at T1. And I don't think either one of us want to accept that idea.