SCCM is dumb when it comes to deciding on the boot.wim to use.
The last advertised TS is how SCCM decides which boot.wim to use.
So if you have a colletion of x86 and x64 machines and you advertise a TS with a x86 boot.wim all systems will boot from the x86 boot.wim first but hte x64 machines will reboot into x64 boot.wim if they pick a x64 TS.
Now if you advertise a x64 TS to this colletion all machines will try to boot off the x64 boot.wim first. obviolusly x86 machines and VMs will fail to boot in this way.
whats really stupid is the PXE knows what architecture is being used. SCCM should force a x86 boot.wim for x86 architectures. As for x64 it really doesnt matter other then having to press "finish" after selecting a TS that doesnt match the TS architecture.
Having seperate collections for x64 and x86 machiens will help control this.
So as the topic says "How do you control the default boot.wim PXE uses?" I really dislike having to re-advertise a TS just to control the boot.wim pxe uses. Plus if the last advertisment was x64 it breaks ALL x86 only machines and VMs.