Cannot boot on the OSX partition

[wseb]

Hello,

I'm running a MacBook/OSX 10.4.11 with an 80G disk. I have (had) 1 extended HFS+ partition with ~16G free space.
I recently tried to resize my single partition with the resizeVolume option of diskUtil (command line). Because it didn't seem to work, I decided to try what's else possible with the graphical Disk Utility tool.
I first tried the option for dividing my main partition when I understood I cannot go back to my old single partition. I checked on the web and found there is a possibility to resize the OSX running partition by booting on a linux live CD and using fdisk or Parted.

Unfortunately, it seems not to be so easy:
*When rebooting the mac I get the terrific question mark screen
*When booting from an Ubuntu live CD everything seems to be OK with the partition table, but when restarting I get the same
*When booting from the OSX install DVD:
-Via the Disk Utility tool I can remove all non OSX partitions and resize the main partition but not apply the changes without reformatting
-Via the diskUtil (command line) I can run a gpt and remove all non OSX partition but not resize anything
-The reinstall tool says I have not the minimum 15G free space on my main partition for reinstalling the system without reformatting it.
*I also tried to install a Unbuntu in the free space. But I ever get this question mark screen however

Has anyone an idea of:
*Why I cannot boot on the OSX partition?
*What I could do for booting on any partition of my disk and/or recovering the data on this unreachable OSX partition?

Many Thanks
Best regards

[Las_Vegas]

If you've messed with the GUID Partition structure and removed the first 200MB EFI partition, your only option is the repartition the drive and start over. I'm strongly suspecting messing with the Partition Map with Ubuntu's utility has rendered your drive un-bootable without repartitioning.

If you haven't changed the start and end of the Mac OS partition and haven't changed the Map type, a little Google searching should find the process of restoring the EFI partition. Once repaired, I don't recommend even trying to use the 16GB available for anything else. You're already low on drive space and Mac OS X won't run stable with much less.

I recommend that you invest in a larger drive for your MacBook if you wish a dual boot system.