How exactly does grub2 works on Macbooks? Does it install Grub2 on the EFI partition and I can boot using the grub loader just as I do on a BIOS based PC? What is actually the consequences of running Linux on EFI? Is it stable?
GRUB2 installs an EFI bootable file into the EFI partiton, the same way OS X does. GRUB is capable of booting Linux, Windows an OS X in EFI mode very similarly to how it works on BIOS-based setups.
The consequence of running Linux on EFI instead of on BIOS is that certain things which depend on a BIOS being present (like the proprietary nVidia drivers, for instance) won’t function. I don’t have any experience with ATI hardware, but I can say that the open-source nouveau driver works quite nicely in EFI mode.
From personal experience I can say that, although it can be somewhat difficult to setup, Linux on EFI is quite stable. I’ve been using Linux almost exclusively on my MacBook Pro for the last 6 months or so without any trouble. Additionally, I can cite the fact that popular Linux distributions (like Ubuntu, for instance) consider this setup quite stable – their stable LiveCDs have implemented this setup for quite a while now.
GRUB 2 works on Macs and has been tested an endless amount of times. Simply put, yes – it works. You will have difficulty in actually obtaining a GRUB EFI image though, so you’ll need to compile one. You can find instructions on the Internet for this.
Yes, GRUB for EFI boots an OS exactly as a BIOS would. However, you asked about drawbacks: well, EFI support in Linux is getting better, but still some video drivers and wireless cards don’t work under Linux in EFI mode.