We received a report from Iomega representative Wayne Linder that the USB2.0 ports found on Apple's PowerBook G4 (Aluminum) and iBook G4 models do not wake from sleep properly, resulting in a lack of functionality:
"After a reviewer told us that one of our new Iomega USB 2.0 UltraMini flash drives failed to mount on his laptop, I did some checking. It seems that on the newer aluminum-clad G4's (and iBooks with USB 2.0), when the computer goes to sleep, the USB port does not properly come back after waking up. Some USB 1.1 devices will power up and mount, but no USB 2.0 devices will. I have duplicated this with our devices and USB drives from M-Systems, C-One, Sony, Lexar and SanDisk. It affects Mac OS 10.2.7, 10.2.8, and I'm currently verifying it with all versions of 10.3. Interestingly, this problem does not happen with the G5. Different chipset, I guess? Thought your readers should know since I have seen some posts in your and Apple's forums, but no solutions."