diff --git a/cmake/CMakeLists.txt b/cmake/CMakeLists.txt
index 12a496cc9f0ab8672f7b53f07f8a5f5afdfb3cda..9d816afa957730b09459cde24c178c457009e20f 100644
--- a/cmake/CMakeLists.txt
+++ b/cmake/CMakeLists.txt
@@ -251,6 +251,7 @@ if(PKG_KSPACE)
   set(FFT_VALUES KISS ${FFTW} MKL)
   set_property(CACHE FFT PROPERTY STRINGS ${FFT_VALUES})
   validate_option(FFT FFT_VALUES)
+  string(TOUPPER ${FFT} FFT)
   if(NOT FFT STREQUAL "KISS")
     find_package(${FFT} REQUIRED)
     if(NOT FFT STREQUAL "FFTW3F")
@@ -790,6 +791,7 @@ if(PKG_USER-INTEL)
     set(INTEL_ARCH_VALUES cpu knl)
     set_property(CACHE INTEL_ARCH PROPERTY STRINGS ${INTEL_ARCH_VALUES})
     validate_option(INTEL_ARCH INTEL_ARCH_VALUES)
+    string(TOLOWER ${INTEL_ARCH} INTEL_ARCH)
 
     if(INTEL_ARCH STREQUAL "knl")
       set(CMAKE_EXE_LINKER_FLAGS  "${CMAKE_EXE_LINKER_FLAGS} -xHost -qopenmp -qoffload")