I have found out something that i think, might be useful for others as well as it's not well known.
How to single boot Linux without delay on Macbook. (tested with Macbook 2.1)
So, I like Macbook, but OSX not at all.
1. If you have OSX installed, boot to it and mute sound. This assures that you won't be annoyed by the startup/poweron sound afterwards. I even used This software to be absolutely sure.
Restart to confirm that no startup sound is audible.
2. Prepare rEFIt boot disk (CD-RW).
3. Boot Ubuntu install and remove all partitions, partition as you like for your Linux installation. Install Ubuntu, restart.
4. Put in rEFIt CD and holding down alt key, boot rEFIT cd. Synchronize GUID and MBR. Restart.
5. Insert OSX disc, boot from it, open terminal and enter following:
where /dev/disk0s2 is the partition you installed grub (do 'diskutil list' to find out correct partition). Of course, '--verbose' is optional. This makes Macbook EFI firmware boot your Linux installation in legacy mode without long delay (20s vs 3s).bless --device /dev/disk0s2 --setBoot --legacy --verbose
6. Restart your Macbook (don't forget to remove OSX disc). And boot directly to Linux!