diff --git a/core/combo/HOST_linux-x86.mk b/core/combo/HOST_linux-x86.mk
index 3001f59..4f35ea7 100644
--- a/core/combo/HOST_linux-x86.mk
+++ b/core/combo/HOST_linux-x86.mk
@@ -24,7 +24,9 @@
 
 # Previously the prebiult host toolchain is used only for the sdk build,
 # that's why we have "sdk" in the path name.
+ifeq ($(strip $(HOST_TOOLCHAIN_PREFIX)),)
 HOST_TOOLCHAIN_PREFIX := prebuilts/tools/gcc-sdk
+endif
 # Don't do anything if the toolchain is not there
 ifneq (,$(strip $(wildcard $(HOST_TOOLCHAIN_PREFIX)/gcc)))
 HOST_CC  := $(HOST_TOOLCHAIN_PREFIX)/gcc