diff --git a/runtime/Makefile b/runtime/Makefile
index 4c0241aa..742cda92 100644
--- a/runtime/Makefile
+++ b/runtime/Makefile
@@ -1,9 +1,9 @@
 XLEN ?= 32
 
 ifeq ($(XLEN),32)
-RISCV_TOOLCHAIN_PATH = /opt/riscv-gnu-toolchain
+RISCV_TOOLCHAIN_PATH ?= /opt/riscv-gnu-toolchain
 else
-RISCV_TOOLCHAIN_PATH = /opt/riscv64-gnu-toolchain
+RISCV_TOOLCHAIN_PATH ?= /opt/riscv64-gnu-toolchain
 endif
 
 RISCV_PREFIX ?= riscv$(XLEN)-unknown-elf-
diff --git a/tests/runtime/fibonacci/Makefile b/tests/runtime/fibonacci/Makefile
index 39c0c751..bc00194e 100644
--- a/tests/runtime/fibonacci/Makefile
+++ b/tests/runtime/fibonacci/Makefile
@@ -1,9 +1,9 @@
 XLEN ?= 32
 
 ifeq ($(XLEN),32)
-RISCV_TOOLCHAIN_PATH = /opt/riscv-gnu-toolchain
+RISCV_TOOLCHAIN_PATH ?= /opt/riscv-gnu-toolchain
 else
-RISCV_TOOLCHAIN_PATH = /opt/riscv64-gnu-toolchain
+RISCV_TOOLCHAIN_PATH ?= /opt/riscv64-gnu-toolchain
 endif
 
 RISCV_PREFIX ?= riscv$(XLEN)-unknown-elf-
diff --git a/tests/runtime/hello/Makefile b/tests/runtime/hello/Makefile
index 3310bf86..a0257cf3 100644
--- a/tests/runtime/hello/Makefile
+++ b/tests/runtime/hello/Makefile
@@ -1,9 +1,9 @@
 XLEN ?= 32
 
 ifeq ($(XLEN),32)
-RISCV_TOOLCHAIN_PATH = /opt/riscv-gnu-toolchain
+RISCV_TOOLCHAIN_PATH ?= /opt/riscv-gnu-toolchain
 else
-RISCV_TOOLCHAIN_PATH = /opt/riscv64-gnu-toolchain
+RISCV_TOOLCHAIN_PATH ?= /opt/riscv64-gnu-toolchain
 endif
 
 RISCV_PREFIX ?= riscv$(XLEN)-unknown-elf-
diff --git a/tests/runtime/simple/Makefile b/tests/runtime/simple/Makefile
index 5f89f366..046b0778 100644
--- a/tests/runtime/simple/Makefile
+++ b/tests/runtime/simple/Makefile
@@ -1,9 +1,9 @@
 XLEN ?= 32
 
 ifeq ($(XLEN),32)
-RISCV_TOOLCHAIN_PATH = /opt/riscv-gnu-toolchain
+RISCV_TOOLCHAIN_PATH ?= /opt/riscv-gnu-toolchain
 else
-RISCV_TOOLCHAIN_PATH = /opt/riscv64-gnu-toolchain
+RISCV_TOOLCHAIN_PATH ?= /opt/riscv64-gnu-toolchain
 endif
 
 RISCV_PREFIX ?= riscv$(XLEN)-unknown-elf-