I recently got a new unibody Macbook from work. Unfortunately, it has a smaller hard drive than my old white Macbook. Since most of the hardware is the same, I thought it might work if I just switch the drives. It does, and system profiler even detects all the right hardware on both computers. However, I can't do a normal reboot. If I try to start up normally, I get a black screen that says "No bootable device. Insert boot disk and press F1" on the unibody machine and a flashing disk with a question mark on the white macbook (which has updated firmware). However, if I hold down Option on startup, my hard drive comes up without a problem and I can continue to boot, select operating system, all as normal. This really gets in the way when installing new software, is a minor annoyance for obvious reasons. Anyone have an idea how to fix it?