With release of Lucid Beta it was time to upgrade my MacBook as well. However the cdrom on my Mac is non functional. I was stuck with using the live usb stick. But unfortunately MacTel EFI firmware has a poor support for booting from USB sticks. There is long list of web pages on net that will tell you to try it once and give up if it doesn't work. The USB stick created with Ubuntu's live image creator did not work at all. It keeps giving message "BOOT ERROR" after the reFIT tries to load the disk.
But all hope is not lost. After a loooooonnnnnng search and countless number of permutations finally I found a solutions. The trick is to make the live USB stick with no partitions. By formatting your USB stick to VFAT directly without creating any partitions on it apple's firmware will be able to boot from it.
However if you format your disk directly with VFAT, the usb disk creator from Ubuntu refuses to use this disk as a target. Asking the utility to format it, will result in the /dev/sdb1 partition being created again. So you will have to create the live image manually. But it does work fine in the end. Read on for full howto.
The instructions are based on this howto
Insert your usb disk and find out which drive it is enumerated as (dmesg will tell you).
For rest of the instructions we will use /dev/sdX, be careful to replace it with appropriate drive since you might otherwise erase you hard disks.
WARNING: use these instructions at your own risk. DO NOT JUST COPY PASTE COMMANDS without understanding the intent. You have been warned, these may burn your house down and kill your dog. I won't be responsible.
1. Format the USB stick
sudo mkfs.vfat /dev/sdX -I
WARNING: this will erase your entire USB stick, no data will be recoverable. Make sure you have already copied whatever you needed to someplace else.
2. Mount the Ubuntu iso to some place
sudo mkdir /media/ubuntu-disk sudo mount -o loop <path-to-ubuntu-iso> /media/ubuntu-disk
3. Mount the usb drive
sudo mkdir /media/usb sudo mount /dev/sdX /media/usb
4. Copy the ubuntu files to USB drive
cd /media/ubuntu-disk sudo cp -rf casper disctree dists install pics pool preseed .disk /media/usb
sudo cp -rf isolinux /media/usb/syslinux sudo cd /media/usb/syslinux sudo mv isolinux.cfg syslinux.cfg
5. Make the disk bootable
sudo aptitude install syslinux mtools cd ~ sudo umount /dev/sdX sudo syslinux /dev/sdX
Thats it the disk should be bootable on Macbook.