diff --git a/cmd/emulator/Dockerfile b/cmd/emulator/Dockerfile
index 0ed9f8cf..99d05e14 100644
--- a/cmd/emulator/Dockerfile
+++ b/cmd/emulator/Dockerfile
@@ -20,7 +20,7 @@ ARG TARGETOS
 ARG TARGETARCH
 ENV GO111MODULE=on \
     CGO_ENABLED=1 \
-    CGO_FLAGS="-O2 -D__BLST_PORTABLE__" \
+    CGO_CFLAGS="-O2 -D__BLST_PORTABLE__" \
     GOOS=$TARGETOS \
     GOARCH=$TARGETARCH
 RUN --mount=type=ssh \