Applied downloaded upgrade of 10.2.5 to 933 G4. Now it will not boot to that boot volume, will boot to other volume w/ 10.2.4 of course (?). Repaired privedges on now non-booting volume, no luck. It will not unmount for regular "repair" in Disk Utility. Complete failure here for some reason.... everything's been pretty smooth up till now, had to see what the update would do to an extra boot volume as an experiment if nothing else... should be bulletproo...