What do you mean with "booting cold"? A "cold-reboot" or booting when Chips are cold? Does that mean PEG boots when chips have warmed up?

When MOS-Kernal is load, you will see a rotating slash during depacking - do you see that?
If you see it, it crashes at next step (starting Kernel after decompression).

Please check following in your OF:

Type in OF:
printenv and check output. What is shown for bootdevice, bootcommand and bootfile.
devalias and look whether there is a entry for CD (should be something like /pci@8000....). If yes,
then insert MOS-Live-CD and type:
boot cd boot.img BM BD=MorphOSBoot

If it works you will enter early startup, where you can check your devices (HD: are all partitions mounted?, etc.)
Then press boot and hopefully Peg boots to Ambient.

One hint: It is reported, that BootCDs, burned on Wintel-PCs are sometimes not working or not properly burned..