Renaming Your EFI Boot Partition
There are two ways of going about this, me personally, would choose to boot into Safe Mode to make this process an adventure, but I'm assuming you want this done quick and efficiently with no hassle. You will want to open up Disk Utility, then from there you should see the EFI Boot Partition in the column to the left with all of your various partitions, drives, and CD's. You should be able to rename it from there. Also, I'm assuming you used rEFIt to create the EFI boot partition because you were trying to boot from a USB drive, but since OS X uses EFI format you weren't able to do that.