RE: Chainloading to other boot loader directly

[Treutwein Bernhard]

If you have the boot loader in a file you can use

chainloader filename
boot

to advise grub to use the bootloader in file filename
and chainload it.

The +1 just tells grub to use the file starting on the default 
device at block offset +1 instead of a file with a name. This 
way to specify files is documented in the grub manual (Grub Legacy:
http://www.gnu.org/software/grub/manual/legacy/File-name-syntax.html#File-name-syntax
 
Grub 2: http://www.gnu.org/software/grub/manual/grub.html#File-name-syntax).

Regards
--
  Bernhard