Originally Posted by Imkantus

Well here comes the -force64 Guide.

When you are using Andy's v4 or v5 Patch Kernel you do not need to patch /usr/lib/dyld itself, only the bindings.

Use the tool posted by Andy to do so, copy amd_insn_patcher to /usr/sbin then use the following Syntax:

amd_insn_patcher /usr/lib/libSystem.B.dylib ~/Desktop/libSystem.B.dylib
amd_insn_patcher /usr/lib/libSystem.B_debug.dylib ~/Desktop/libSystem_debug.B.dylib
amd_insn_patcher /usr/lib/libSystem.B_profile.dylib ~/Desktop/libSystem.B_profile.dylib

Last two ones are only present if Xcode is installed on your system.
The patched files will appear on your Desktop, use "open /usr/lib" on Terminal to open the folder, open Disk-Utility, replace the three files by dropping them into /usr/lib by Finder. Select your harddrive in Disk-Utility and run Repair Permissions Task, wait till it is done and reboot.

After reboot open Terminal again and run the following command:

sudo update_dyld_shared_cache

Now for the AMD users out there, there are still CPUIDs left to patch, this can be done using amd_insn_patcher too, but this is laborious, so I have made a cpuid.txt that only needs to be dropped onto Maxxus Patcher GUI Icon - get it from the attachment. (Note that you will need to patch more files than those in that file, if you are going to use pure legacy i386 mode / without -force64)

This is what is giving me a fully working AMD system.