Hi

usbboot is subdirectory in xburst-tools. here is the step to separate usbboot to an individual Git repository:

<> git clone –no-hardlinks git://projects.qi-hardware.com/xburst-tools.git xburst-tools.tmp
<> cd xburst-tools.tmp/
<> git filter-branch –subdirectory-filter usbboot HEAD
<> git reset –hard
<> git gc –aggressive
<> git prune

The following command will remove [usbboot] from within [xburst-tools].

git filter-branch --tree-filter "rm -rf usbboot" --prune-empty HEAD
git reset --hard
git gc --aggressive
git prune

Of course, test it in a ‘clone –no-hardlinks’ repository first, and follow it with the reset, gc and prune commands Paul lists.

for more information :

http://stackoverflow.com/questions/359424/detach-subdirectory-into-separate-git-repository