diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index cbc68378b..fe31b5960 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -138,6 +138,10 @@ jobs:
             fi
           fi
 
+          if [[ '${{ runner.os }}' == 'Windows' ]]; then
+            export NIMFLAGS="${NIMFLAGS} --cc:clang"
+          fi
+
           export NIMFLAGS="${NIMFLAGS} ${{ matrix.nimflags-extra }}"
           echo "NIMFLAGS=${NIMFLAGS}" >> $GITHUB_ENV
 
@@ -178,7 +182,7 @@ jobs:
 
       - name: Build binaries (with trace logging enabled)
         run: |
-          ${make_cmd} -j ${ncpu} V=1 NIM_COMMIT=${{ matrix.branch }} LOG_LEVEL=TRACE NIMFLAGS="-u:release --opt:none ${{ matrix.nimflags-extra }}"
+          ${make_cmd} -j ${ncpu} V=1 NIM_COMMIT=${{ matrix.branch }} LOG_LEVEL=TRACE NIMFLAGS="-u:release --opt:none ${NIMFLAGS}"
           # The Windows image runs out of disk space, so make some room
           rm -rf build nimcache
 
diff --git a/vendor/nim-ssz-serialization b/vendor/nim-ssz-serialization
index 248f2bdca..ec87026c9 160000
--- a/vendor/nim-ssz-serialization
+++ b/vendor/nim-ssz-serialization
@@ -1 +1 @@
-Subproject commit 248f2bdca2d65ff920920c72b764d0622d522596
+Subproject commit ec87026c914f7be7951e016d7dfb33b061f92b35