diff --git a/build/scripts/build_cross_tools b/build/scripts/build_cross_tools
index 9e2fd4edb0..37b7616b85 100755
--- a/build/scripts/build_cross_tools
+++ b/build/scripts/build_cross_tools
@@ -20,7 +20,7 @@ additionalMakeArgs=$*
 	# additional flags for the binutils build. Should there ever be any other
 	# flags than -jN, we need to handle this differently.
 
-if [ `uname -o` = 'Haiku' ]; then
+if [ `uname -s` = 'Haiku' ]; then
 	# force cross-build if building on Haiku:
 	buildhostMachine=i586-pc-haiku_buildhost
 	buildHostSpec="--build=$buildhostMachine --host=$buildhostMachine"
diff --git a/build/scripts/build_cross_tools_gcc4 b/build/scripts/build_cross_tools_gcc4
index f9b6023532..2d587720c6 100755
--- a/build/scripts/build_cross_tools_gcc4
+++ b/build/scripts/build_cross_tools_gcc4
@@ -50,7 +50,7 @@ arm-*)
 	;;
 esac
 
-if [ `uname -o` = 'Haiku' ]; then
+if [ `uname -s` = 'Haiku' ]; then
 	# force cross-build if building on Haiku:
 	buildhostMachine=${haikuMachine}_buildhost
 	buildHostSpec="--build=$buildhostMachine --host=$buildhostMachine"