mac pro G5 boot issue- Leopard and Yellow Dog 6.2 installed Heres a killer. My Mac Pro g5 was running Leopard, fully updated, quite fine. But, since Im an idiot tinkerer who loves linux as mich as Mac, I decided to stupidly install YDL. Now, it ran flawlessly for a few months, until I packed the machine away while I moved house. Now, YDL boots quite fine... but MacOS refuse to move anywhere past the Apple Logo. I get no spinning Wheel, just the bitten apple on a grey screen and the machine sitsthere...
So far, I reseated ram, reset NVRAM, reset PRAM, theres no password on OF, I even used the button thing on the motherboard to reset. Nothing. The drive is fine and readable... YDL And Leopard are installed on the same drive, differentpartitions. No keypress combination works since Yaboot is installed- I can only use alt to select a boot device ()this displays the YDL and Leopard disks, but when I choose the Leopard disk, I get the grey screen.

Unfortunately, I do not have access to a Leopard install fisk and have absolutely no hope of getting one. 
I also have no internet access on the machine.

If ANYONE can point me in the right direction, Ill be eternally grateful!!

Txs in advance,
Brendan
Problem solved! So, I decided that, since Im desperate, Im gonna do what I have to. I deleted the partition with Yellowdog on it, then messed with the firmware a lot. I managed to find a way to get it to boot straight to MacOS... and then used Cmd-S to boot into single usermode and surprise surprise, AppleJack rescued my machine in 4 passes. 

Incidentally, after I managed to get the machine sorted, some kind soul sent me a Leopard Install Disk. Retail. 

Nice!