It seems as though the minimum system requirements are still in force in Aperture 1.5, which means that although 1.25GHz PowerBooks are supported, my dual 867GHz MDD isn’t, which is rather odd. Still, the hack for Aperture 1.1 still works on 1.5, but the offsets have (unsurprisingly) moved a little.
Using a hex editor (I found 0xed very useful), try changing the following:
0×0b548: 40 9E 00 88 -> 48 00 00 88
0×0b5e4: 40 9E 00 88 -> 48 00 00 88
0×17390: 40 9E 00 E0 -> 48 00 00 D8
The updated binary has been tested on both an 2GB MDD 867GHz PowerMac and also a 768MB 1GHz 12″ PowerBook, but note that the Info.plist file might still need tweaking to remove the minimum RAM check.
Enjoy !