diff --git a/.github/workflows/build_all.yml b/.github/workflows/build_all.yml
index 4cce0dc83a1d..7e4f7ed3333d 100644
--- a/.github/workflows/build_all.yml
+++ b/.github/workflows/build_all.yml
@@ -15,7 +15,7 @@ jobs:
     strategy:
       matrix:
         # Keep these names short due to questionable Github UI choices
-        IPC: [ipc3, ipc4]
+        IPC: [3, 4]
 
     steps:
       - name: add i386 arch
@@ -65,5 +65,5 @@ jobs:
           cd workspace
           clang --verbose
           set -x
-          sof/scripts/fuzz.sh -b -- -DEXTRA_CFLAGS='-Werror' -DEXTRA_CXXFLAGS='-Werror' \
-              -DEXTRA_CONF_FILE='stub_build_all_${{ matrix.IPC }}.conf'
+          sof/scripts/fuzz.sh -b -"$ipc" -- -DEXTRA_CFLAGS='-Werror' -DEXTRA_CXXFLAGS='-Werror' \
+              -DEXTRA_CONF_FILE='stub_build_all_ipc${{ matrix.IPC }}.conf'
diff --git a/.github/workflows/ipc_fuzzer.yml b/.github/workflows/ipc_fuzzer.yml
index b7b0c6e55f95..166b64ca67bd 100644
--- a/.github/workflows/ipc_fuzzer.yml
+++ b/.github/workflows/ipc_fuzzer.yml
@@ -78,13 +78,13 @@ jobs:
           clang --verbose
           set -x
           case '${{ matrix.IPC }}' in
-            IPC3) cmake_arg='-DCONFIG_IPC_MAJOR_3=y' ;;
-            IPC4) cmake_arg='-DCONFIG_IPC_MAJOR_4=y' ;;
+            IPC3) _ipc='-3' ;;
+            IPC4) _ipc='-4' ;;
           esac
           duration="${{inputs.fuzzing_duration_s}}"
           duration="${duration:-301}"  # pull_request has not 'inputs.' :-(
           # Note libFuzzer makes a difference between -jobs and -workers (capped at nproc/2)
-          sof/scripts/fuzz.sh -o fuzz-stdout.txt -t "$duration" -j"$(nproc)" -- "$cmake_arg"
+          sof/scripts/fuzz.sh "$_ipc" -o fuzz-stdout.txt -t "$duration" -j"$(nproc)"
 
       - name: Upload stdout
         uses: actions/upload-artifact@v4