I`m also having the same problem.
after i restore Empire efi to the partition I can`t get it to boot.
the diskutil list shows like this:
/dev/disk0
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *320.1 GB disk0
1: EFI 209.7 MB disk0s1
2: Apple_HFS snow 42.4 GB disk0s2
3: Apple_HFS seven 36.8 GB disk0s3
4: Apple_HFS store 240.3 GB disk0s4
/dev/disk1
#: TYPE NAME SIZE IDENTIFIER
0: FDisk_partition_scheme *8.1 GB disk1
1: Apple_HFS Empire EFI 100.0 MB disk1s1
2: Apple_HFS Mac OS X Install DVD 8.0 GB disk1s2

would appreciate any help...