--- a/toolkit/mozapps/installer/packager.mk
+++ b/toolkit/mozapps/installer/packager.mk
@@ -472,17 +472,17 @@ INNER_UNMAKE_PACKAGE	= \
   set -ex; \
   rm -rf $(_ABS_DIST)/unpack.tmp; \
   mkdir -p $(_ABS_DIST)/unpack.tmp; \
   $(_ABS_MOZSRCDIR)/build/package/mac_osx/unpack-diskimage $(UNPACKAGE) /tmp/$(MOZ_PKG_APPNAME)-unpack $(_ABS_DIST)/unpack.tmp; \
   rsync -a '$(_ABS_DIST)/unpack.tmp/$(_APPNAME)' $(MOZ_PKG_DIR); \
   test -n '$(MOZ_PKG_MAC_DSSTORE)' && \
     rsync -a '$(_ABS_DIST)/unpack.tmp/.DS_Store' '$(MOZ_PKG_MAC_DSSTORE)'; \
   test -n '$(MOZ_PKG_MAC_BACKGROUND)' && \
-    rsync -a '$(_ABS_DIST)/unpack.tmp/.background/`basename '$(MOZ_PKG_MAC_BACKGROUND)'`' '$(MOZ_PKG_MAC_BACKGROUND)'; \
+    rsync -a '$(_ABS_DIST)/unpack.tmp/.background/$(notdir $(MOZ_PKG_MAC_BACKGROUND))' '$(MOZ_PKG_MAC_BACKGROUND)'; \
   test -n '$(MOZ_PKG_MAC_ICON)' && \
     rsync -a '$(_ABS_DIST)/unpack.tmp/.VolumeIcon.icns' '$(MOZ_PKG_MAC_ICON)'; \
   rm -rf $(_ABS_DIST)/unpack.tmp; \
   if test -n '$(MOZ_PKG_MAC_RSRC)' ; then \
     cp $(UNPACKAGE) $(MOZ_PKG_APPNAME).tmp.dmg && \
     hdiutil unflatten $(MOZ_PKG_APPNAME).tmp.dmg && \
     { /Developer/Tools/DeRez -skip plst -skip blkx $(MOZ_PKG_APPNAME).tmp.dmg > '$(MOZ_PKG_MAC_RSRC)' || { rm -f $(MOZ_PKG_APPNAME).tmp.dmg && false; }; } && \
     rm -f $(MOZ_PKG_APPNAME).tmp.dmg; \