diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9f15c73dc..b65c4ada3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -65,10 +65,10 @@ else()
   set(ARCH_ID "${ARCH}")
 endif()
 string(TOLOWER "${ARCH_ID}" ARM_ID)
-string(SUBSTRING "${ARCH_ID}" 0 3 ARM_TEST)
+string(SUBSTRING "${ARM_ID}" 0 3 ARM_TEST)
 if (ARM_TEST STREQUAL "arm")
   set(ARM 1)
-  string(SUBSTRING "${ARCH_ID}" 0 5 ARM_TEST)
+  string(SUBSTRING "${ARM_ID}" 0 5 ARM_TEST)
   if (ARM_TEST STREQUAL "armv6")
     set(ARM6 1)
   endif()
@@ -77,7 +77,7 @@ if (ARM_TEST STREQUAL "arm")
   endif()
 endif()
 
-if (ARCH_ID STREQUAL "aarch64")
+if (ARM_ID STREQUAL "aarch64")
   set(ARM 1)
   set(ARM8 1)
 endif()