iMac won't boot from USB but MBP will?

Hello

I have made a bootable version of snow leopard on my USB key. I partitioned the drive correctly, restored the dmg to the USB key correctly, etc
When I tested in on my MacBook pro, on start up I held alt, selected the USB drive to boot from and it booted just fine into the install Mac OSX screen, asking me what language I want to use, etc.
However, the reason I made the boot is for my iMac.
When I try to boot from that drive on my iMac, it goes to a white screen with an apple after selecting the drive, it then just sits there indefinitely. The USB key has a light on it indicating it is in use. The light goes out, and nothing happens.
Any idea why this would work on a older intel dualcore macbook pro and not work on my 2010 i3 iMac?

Thanks

caiken76 said:

I have made a bootable version of snow leopard on my USB key. I partitioned the drive correctly, restored the dmg to the USB key correctly, etc

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Any idea why this would work on a older intel dualcore macbook pro and not work on my 2010 i3 iMac?

Click to expand...

Did you update it to at least 10.6.3? If not, do so. Those model iMacs came with 10.6.3 pre-installed and won't boot anything earlier due to lack of drivers. You may as well just update all the way to 10.6.8.

If that doesn't work, and if you made the USB key with an OEM install disk that came with that MBP, then that may be the problem. The OEM disks lack drivers for anything but the specific Mac model they came with.