diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 27f9ddd6..490d4c05 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -35,6 +35,7 @@ jobs:
       - name: Extract seL4CP SDK
         run: unzip sel4cp-sdk.zip && tar -xf sel4cp-sdk-1.2.6.tar.gz
       - name: Install VMM dependencies (via apt)
+        # 'expect' is only a dependency for CI testing
         run: sudo apt update && sudo apt install -y make clang lld qemu-system-arm device-tree-compiler expect
       - name: Build and run VMM examples
         run: ./ci/examples.sh ${PWD}/sel4cp-sdk-1.2.6
@@ -58,9 +59,10 @@ jobs:
       - name: Extract seL4CP SDK
         run: unzip sel4cp-sdk.zip && tar -xf sel4cp-sdk-1.2.6.tar.gz
       - name: Install VMM dependencies (via Homebrew)
+        # 'expect' is only a dependency for CI testing
         run: |
-          brew tap messense/macos-cross-toolchains
-          brew install aarch64-unknown-linux-gnu qemu dtc make expect
+          brew install llvm qemu dtc make expect
+          echo "/usr/local/opt/llvm/bin:$PATH" >> $GITHUB_PATH
       - name: Build and run VMM examples
         run: ./ci/examples.sh ${PWD}/sel4cp-sdk-1.2.6
         shell: bash
diff --git a/ci/examples.sh b/ci/examples.sh
index f79ee372..fa79eeb9 100755
--- a/ci/examples.sh
+++ b/ci/examples.sh
@@ -7,24 +7,30 @@ SDK_PATH=$1
 [[ -z $SDK_PATH ]] && echo "usage: examples.sh [PATH TO SDK]" && exit 1
 [[ ! -d $SDK_PATH ]] && echo "The path to SDK provided does not exist: '$SDK_PATH'" && exit 1
 
-build_simple() {
+build_simple_make() {
     BOARD=$1
     CONFIG=$2
-    BUILD_DIR="build_simple_${CONFIG}_${BOARD}"
-    make -C examples/simple -B BUILD_DIR=${BUILD_DIR} CONFIG=${CONFIG} BOARD=${BOARD} SEL4CP_SDK=${SDK_PATH}
+    BUILD_DIR="${PWD}/build/simple/make/${BOARD}/${CONFIG}"
+    mkdir -p ${BUILD_DIR}
+    make -C examples/simple -B \
+        BUILD_DIR=${BUILD_DIR} \
+        CONFIG=${CONFIG} \
+        BOARD=${BOARD} \
+        SEL4CP_SDK=${SDK_PATH} \
+        -j$(nproc)
 }
 
-simulate_simple() {
+simulate_simple_make() {
     BOARD=$1
     CONFIG=$2
-    BUILD_DIR="build_simple_${CONFIG}_${BOARD}"
-    ./ci/buildroot_login.exp examples/simple/${BUILD_DIR}/loader.img
+    BUILD_DIR="${PWD}/build/simple/make/${BOARD}/${CONFIG}"
+    ./ci/buildroot_login.exp ${BUILD_DIR}/loader.img
 }
 
-build_simple "qemu_arm_virt_hyp" "debug"
-simulate_simple "qemu_arm_virt_hyp" "debug"
-build_simple "qemu_arm_virt_hyp" "release"
-simulate_simple "qemu_arm_virt_hyp" "release"
+build_simple_make "qemu_arm_virt_hyp" "debug"
+simulate_simple_make "qemu_arm_virt_hyp" "debug"
+build_simple_make "qemu_arm_virt_hyp" "release"
+simulate_simple_make "qemu_arm_virt_hyp" "release"
 
-build_simple "odroidc4_hyp" "debug"
-build_simple "odroidc4_hyp" "release"
+build_simple_make "odroidc4_hyp" "debug"
+build_simple_make "odroidc4_hyp" "release"
diff --git a/examples/simple/Makefile b/examples/simple/Makefile
index b15bfbf5..820b0bc0 100644
--- a/examples/simple/Makefile
+++ b/examples/simple/Makefile
@@ -85,11 +85,14 @@ endif
 # FIXME: We should also consider whether -mgeneral-regs-only should be
 # used to avoid the use of the FPU and therefore seL4 does not have to
 # context switch the FPU.
+# Note we only need -Wno-unused-command-line-argument because in Nix
+# passes an extra `--gcc-toolchain` flag which we do not need.
 CFLAGS := -mstrict-align \
 		  -g3 \
 		  -O3 \
 		  -ffreestanding \
 		  -nostdlib \
+		  -Wno-unused-command-line-argument \
 		  -Wall -Wno-unused-function -Werror \
 		  -I$(VMM_SRC_DIR)/arch/aarch64 -I$(VMM_SRC_DIR) -I$(VMM_SRC_DIR)/util -I$(BOARD_DIR)/include \
 		  -DBOARD_$(BOARD) \