Boot FreeLoader from GRUB

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Revision as of 03:33, 23 October 2010 by CycleGeek (talk | contribs)
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GRUB is a popular boot manager for people with many different operating systems installed on one machine or hard disk. FreeLoader is the bootloader for ReactOS and also a possible boot manager. If you have GRUB already installed and then install ReactOS, FreeLoader's abilities become redundant and annoying. This document shows how to keep FreeLoader from doing much but acting as a bootloader for ReactOS.


FreeLoader can be loaded as a "multiboot kernel" by multiboot compliant bootstrap loaders like GRUB. To load FreeLoader from GRUB, put something like this in the GRUB's menu.lst configuration file:

title		ReactOS
root		(hd0,0)
kernel		/freeldr.sys


  • (hd0,0) refers to the first partition on the first disk.
  • (hd1,0) refers to the first partition on the second disk.
  • (hd0,1) refers to the second partition on the first disk.

You should make sure that the path referred to by "kernel" and freeldr.sys is on a FAT16/32 partition.

You can also override settings in the [FREELOADER] section of FreeLoader's freeldr.ini configuration file by passing them on the command like, like this:

title	ReactOS
root	(hd0,0)
kernel	/freeldr.sys DefaultOS=ReactOS TimeOut=0

title	ReactOS (Debug)
root	(hd0,0)
kernel	/freeldr.sys DefaultOS=ReactOS_Debug TimeOut=0

After selecting "ReactOS" from the GRUB menu you will not have to make another selection on the freeloader menu because of the TimeOut=0.


The next generation of GRUB, GRUB 2 uses other language in its configuration file grub.cfg. Here is an example how to add a menu entry for ReactOS:

menuentry "ReactOS" {
	set root=(hd0,1)
	multiboot /freeldr.sys

Note that partition numbering has been changed, and (hd0,1) refers to the first partition on the first disk.