GPT specific instructions
GRUB2 in BIOS-GPT configuration requires a BIOS Boot Partition to embed its core.img in the absence of 32 KiB post MBR gap in GPT partitioned systems.
Create a 1 MiB (minimum size) partition using gdisk or GNU Parted with no filesystem. The location of the partition in the partition table does not matter but it should be within the first 2 TiB region of the GPT disk. It is advisable to put it somewhere in the beginning of the disk before the /boot partition. Set the partition type to "EF02" in GPT fdisk or set "bios_grub" flag on in GNU Parted or GParted.
This partition is used by GRUB2 only in BIOS-GPT setups. No such partition type exists in case of MBR partitioning (at least not for GRUB2). This partition is also not required if the system is UEFI based, as no embedding takes place in that case. Neither GRUB-legacy nor SYSLINUX require this partition.
Note: This partition should be created before grub_bios-install or grub-setup is run or before the Install Bootloader step of the Archlinux installer (if GRUB2 is selected as bootloader).