GRUB2

GRUB2

1. /boot/grub2/boot.cfg

   • automatically generated by grub-mkconfig
     • Use templates from
       • /etc/grub.d
         • 00_header, 10_linux, 20_memtest86, 30_os-prober, 40_custom, 90_persistent
       • /etc/default/grub
         • Grub menu timeout, hidden menu, theme, background etc
   • Don't edit manually

2. IDE/SCSI drives count from Zero eg hd0,msdos1 is the first partition on the first drive

3. SATA Drives count from ONE eg sda1,msdos1 is the first partition on the first drive

4. boot image files /usr/lib/grub(2)/<cpu>-<platform> eg /usr/lib/grub2/i386-pc

5. Installation Types

   • MBR
     • Normally embedded between the MBR and the first partition (MBR Gap/ Embedding Area).
       • 1st Partition should start min 63 sectors from start of disk. Newer drives aligned to larger boundries so reserve 1 MiB
   • GPT
     • Some newer systems use GUID Partition Table (Part of EFI)
       • Reserve whole partition for GRUB called BIOS Boot Partition
         • Recommend min 1MiB and partition type set to "bios_grob on" or "0xEF02"

6. TWO BOOT OPTIONS

   • Boot OS directly
     • grub> root (hd0,2)
       • Load the kernel and set root eg grub> linux /vmlinuz-2.6.32 ro root=UUID=<unique number of partition with OS>
         • Start Initial Ram Disk eg grub> initrd /initramfs-2.6.32.img
           • grub> boot
   • Chain-loading another boot loader
     • DOS / Win must be chainloaded