Again also in the comments:
Was playing with EFI partition boot. My disk was identified as an GPT/MBR disk. Everything is copied over fine to disk0s1 including boot, but the EFI partition is not made active. I see in the script that it only makes the EFI partition active for a GPT disk, not for an GPT/MBR disk. Bug?
If I make the EFI partition active myself and reboot it stops after:
boot0; GPT
boot0: testing
boot0: done
Seems it does not continue with boot1, but it is dd-ed to that partition.
If I make disk0s2 active I need to have boot in the root of the OS X partition or else I get boot1: error. If boot is there, everything else is loaded from the EFI partition fine.
Seems to me that the intended behavior is to have boot1 and boot both at the EFI partition, right?