For CFB mode, the main requirement on the IV is that you don't reuse the same IV to encrypt two different messages. If you do, the consequences are only moderately bad (the attacker learns the xor of the two initial plaintext blocks of the two messages, and more if those two plaintext blocks happen to be the same), it's probably best to avoid that. It doesn't matter if the IV is predictable (unlike CBC mode); non-reuse is the only requirement.
That said, there are a number of ways to achieve it. The first obvious one (generate them using a counter) probably doesn't apply to you (as you may not have any place to store them over reboots). On the other hand, picking them randomly works (and, unlike most uses of RNGs in crypto, it doesn't have to be that strong - again, we're only looking to avoid reuse). A third approach would be to generate a Message Authentication Code of the plaintext (based on a secret key) and use that as your IV - that would make it obvious when you are encrypting the same message twice (the ciphertexts will be exactly the same); however it doesn't rely on an external RNG or entropy source.