diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7bac623..affc07d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -153,7 +153,7 @@ if (Threads_FOUND)
 endif()
 
 option(NO_SELF_PACKER "Disables usage of a self-packer")
-if (NOT (CMAKE_BUILD_TYPE STREQUAL "Debug" OR CMAKE_BUILD_TYPE STREQUAL "RelWithDebInfo" OR NO_SELF_PACKER OR DEFINED EMSCRIPTEN OR MINGW))
+if (NOT (UPPERCASE_BUILD_TYPE STREQUAL "DEBUG" OR UPPERCASE_BUILD_TYPE STREQUAL "RELWITHDEBINFO" OR NO_SELF_PACKER OR DEFINED EMSCRIPTEN OR MINGW))
     include(FindSelfPackers)
     if (SELF_PACKER_FOR_EXECUTABLE MATCHES upx)
         set(SELF_PACKER_FOR_EXECUTABLE_FLAGS ${SELF_PACKER_FOR_EXECUTABLE_FLAGS} --ultra-brute --best)