If u still have problem with booting in leopard here is my advice for u all.
I was trying to boot leopard but no success. I was using Tiger to boot in Leopard and try this thing then:
1. Format hdd or partition where was tiger and Leopard
2. Install tiger becouse boot loader is working on tiger and before u start to tiping your name and password restart
3. Install Leopard AMD 10.5.1 and go in safe mod after f8 us -x for safemod and remove GeForce and NV kexts
4. Restart and boot normaly in Leopard without DVD becouse Leopard have boot loader from tiger now and work's fine
5. If u boot without going in safe modthat is bether becouse i had to remove geforce and nv kext's to make it work

So this is my way harder but 100% work. I am not smart ass but just trying to help.
Good luck to us all.
See u soon.

ok that explains it, thanks mate

roisoft: I'll give it a go although my mac partition is already booting fine.

I think that your device tree is something like this, right?

disk0s1 --->tiger (default boot)
disk0s2 --->Leopard

In the rev1 you must activate the partiton manually and in your case Darwin is intalled from the tiger partition not from leo....

fdisk -e /dev/rdisk0
update

f 2

w (y)

q

cd /usr/standalone/i386

./startupfiletool -v /dev/rdisk0s2 ./boot

Hey guys is there any manual how to edit Leopard DVD ( to add more software to install in post install process).
I wont for example to remove geforce kext's becouse they making problem in starting leopard and to add my drivers for my VGA.
This is not the topic for here but just I'm asking and sory for this question.
Thanks in advance.

roisoft my device tree is like this..

disk0s1 --->Leo
disk0s2 --->7gb spare for disk images
disk0s3 ---> Tiger (default boot)

when I went to use startupfiletool it said "could not find file". All I had in i386 was a boot1h, so I replaced ./boot with ./boot1h and it worked fine however Tiger is still default in boot menu. I give up for now. I'm going to format the drive and get rid of Tiger anyway when Rev 2 comes out. Thanks for the effort to try and get this sorted for me.

try with this file