diff --git a/.github/workflows/build-os.yml b/.github/workflows/build-os.yml
index 3d4b267..c122aad 100644
--- a/.github/workflows/build-os.yml
+++ b/.github/workflows/build-os.yml
@@ -74,6 +74,13 @@ jobs:
           cmake -S . -B build-cmake \
             -DCMAKE_BUILD_TYPE=Release \
             -DNO_COLOR=1 \
+            -DCC=gcc \
+            -DKERNEL_CXX=g++ \
+            -DLD=ld.lld \
+            -DUSER_CC=cc \
+            -DUSER_LD=ld.lld \
+            -DNM=llvm-nm \
+            -DADDR2LINE=llvm-addr2line \
             -DLIMINE_REPO=https://github.com/limine-bootloader/limine.git
 
       - name: Build ISO
diff --git a/CMakeLists.txt b/CMakeLists.txt
index a1abf84..6ae5e08 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -56,16 +56,20 @@ function(resolve_tool_with_fallback VAR_NAME)
         endif()
         set(_resolved "${_requested}")
     else()
+        unset(_requested_path CACHE)
+        unset(_requested_path)
         find_program(_requested_path NAMES "${_requested}")
         if(_requested_path)
-            set(_resolved "${_requested}")
+            set(_resolved "${_requested_path}")
         else()
             set(_resolved "")
             foreach(_cand IN LISTS _fallbacks)
+                unset(_cand_path CACHE)
+                unset(_cand_path)
                 find_program(_cand_path NAMES "${_cand}")
                 if(_cand_path)
                     cl_log_warn("${VAR_NAME} '${_requested}' not found; fallback to '${_cand}'")
-                    set(_resolved "${_cand}")
+                    set(_resolved "${_cand_path}")
                     break()
                 endif()
             endforeach()