I created a Fedora 15 "live" USB stick using the live USB creator found at https://fedorahosted.org/liveusb-creator/ and the Fedora 15 i686 Desktop ISO image with the persistent storage space set to 4096MB. (The USB stick I have available has an 8GB capacity, so there should be plenty of space.)

Fedora appears to boot correctly, however it seems that the persistent storage is not working. To verify this, I opened a terminal prompt, then did su - followed by yum update yum. As expected, I was informed that a new version was available. (The live CD contains version 3.2.29-4, at the time of typing 3.2.29-6 is the current version). After installing, I verified that the new version was installed by typing yum --version. I then shutdown the system using shutdown now.

After the system had shut down, I rebooted and returned to the terminal prompt. On typing yum --version, I was informed that the version was 3.2.29-4 (i.e. the original version).

Why might the persistent storage not be working? Is there anything I can do to fix it?