Grub2

https://help.ubuntu.com/community/Grub2

GRUB 2's major improvements

• Scripting support including conditional statements and functions
• Dynamic module loading
• Rescue mode
• Custom Menus
• Themes
• Graphical boot menu support and improved splash capability
• Boot LiveCD ISO images directly from hard drive
• New configuration file structure
• Non-x86 platform support (such as PowerPC)
• Universal support for UUIDs (not just Ubuntu)

gentoo grub2 resources

For information on how to configure GRUB2 please refer to the guide: GRUB2_Quick_Start

A migration guide for GRUB Legacy users is available: grub2 migration

Install sys-boot/os-prober to enable detection of other operating systems using grub2-mkconfig.

Install dev-libs/libisoburn to enable creation of rescue media using grub2-mkrescue.