diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4466829..ea6ad05 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -150,10 +150,6 @@ jobs:
 
       - name: Run tests
         run: |
-          if [[ "${{ matrix.target.os }}" == "windows" ]]; then
-            # https://github.com/status-im/nimbus-eth2/issues/3121
-            export NIMFLAGS="-d:nimRawSetjmp"
-          fi
           nim --version
           nimble --version
           nimble install -y --depsOnly
diff --git a/nim.cfg b/nim.cfg
new file mode 100644
index 0000000..371f6d7
--- /dev/null
+++ b/nim.cfg
@@ -0,0 +1,5 @@
+# Avoid some rare stack corruption while using exceptions with a SEH-enabled
+# toolchain: https://github.com/status-im/nimbus-eth2/issues/3121
+@if windows and not vcc:
+  --define:nimRawSetjmp
+@end
diff --git a/tests/nim.cfg b/tests/nim.cfg
new file mode 100644
index 0000000..371f6d7
--- /dev/null
+++ b/tests/nim.cfg
@@ -0,0 +1,5 @@
+# Avoid some rare stack corruption while using exceptions with a SEH-enabled
+# toolchain: https://github.com/status-im/nimbus-eth2/issues/3121
+@if windows and not vcc:
+  --define:nimRawSetjmp
+@end