Can't boot Ubuntu 12.04 from external Hard Drive using Mac

view full story

http://askubuntu.com – Recently, I upgraded the RAM and hard drive on my Early 2008 Macbook to improve the performance. Rather than throw away the old hard drive, I bought an enclosure for it to turn it into an external hard drive, and, since all the data was migrated to my new drive, I decided to install Ubuntu on it for funsies (note: I am a near-total Ubuntu n00b). My first attempt to install Ubuntu didn't work (it gave me errors about not being able to find the BIOS or something), but my second attempt finished successfully (can't remember what, if anything, I did different). However, when I plug the exter (HowTos)