Powermac G5 have two SATA I connectors. You not need any master/slave select, it is PATA behavior.
There will be something other.
What is your partition map? And do you use linux or MacOS X on this Powermac? I recommend not to mix hdtools from different systems, it often causes partition mismatch.
AmigaOS3: Amiga 1200
AmigaOS4: Micro A1-C, AmigaOne XE, Pegasos II, Sam440ep, Sam440ep-flex, AmigaOneX1000
MorphOS: Efika 5200b, Pegasos I, Pegasos II, Powerbook G4, Mac Mini, iMac G5, Powermac G5 Quad