You will need to partition/format the disk using "Apple Partition Map" and re-install Mac OS X. About the only way you can upgrade is to swap out the entire main logic board for a new Intel board. But it is to slow for my current needs so my plan is to upgrade it. It is absolutly 100 OK by Apple to run Mac OS on this. I have an old G4 'Digital Audio' model tower.
Most any 3.5" SATA disk will work although I would keep it relatively small (less than 250GB) as some of the earlier PowerMac G5s had firmware limitations on hard drive capacity. Apple only allows you to install Mac OS X on an 'Apple labeled computer'. More than likely replacing the startup disk WILL fix the issue. With AHT (the diagnostic you ran) already reporting an error this is likely the scenario. If the Mac doesn't boot to verbose mode and instead only shows the flashing folder icon again then I would again assume a hardware failure. I would be on the lookout for "Disk I/O" errors, these will indicate a hardware failure with the hard drive itself. Power your Mac on while holding command+ V (Apple + V if an older keyboard).Īssuming the disk isn't completely failed this should boot the Mac in verbose mode, where you can read what is occurring as the Mac is attempting to boot. To diagnose the issue you could try this. Since there are two drive bays, where the two SATA disks are aligned vertically, I would interpret the error as meaning the upper disk is having the problem. Depending on your G5 PowerMac you might have dual processors but these are usually referred to as A or B and would throw a CPU error rather than STF. The AHT error code more than likely stands for SATA Function or something similar, and since it references "upper" I would interpret that as the upper of two items.This can be a result of a badly corrupted operating system (often resulting from impending hard drive failure), a failed hard drive or a new unformatted hard drive. The gray screen with an flashing folder icon occurs when the Mac cannot find a valid OS X system to boot to.It's not as common, but is far from uncommon to hear beep error tones from failing hard drives as well. Failing hard drives often make loud clicking sounds.More than likely the hard drive in the upper bay is failing.