Booting of a HD isnt so easy cause i want to install the OS to a powerbook. Meaning, only USB ports and non powered. Ok anyway suppose i do it, do i just leave the dmg in the partition? Is that enough? and then what? do i boot ressing alt and choosing the ext drive?
I think I already posted to your main forums question about this, but:
If the .dmg is good, then burning that to a DVD should end up being bootable. There's no settings, AFAIK, that need to be set to make it bootable. It either is - or you have a bad burn, so try again.
It must be on a dual-layer DVD, as the disk SHOULD make about 7.8 GB as a final DVD.
Assume that one that won't boot is a bad burn, so burn another copy, with another brand of DVD, etc.
You can choose to be surprised if the DVD does boot a Mac, as I have burned a lot of 10.5 coasters, leading to the conclusion that a burned DVD is not your best choice with Leopard.
My suggestion is to forget the DVD, and make a dedicated partition (8GB is great) on an external hard drive. Run Disk Utility, and restore that .dmg to the 7GB partition.
It . works . every . time and is a faster install, as well as being more reliable than the DVD will be.