diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 0887d628..aacd7a56 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -41,9 +41,12 @@ jobs:
             docker pull artifactory.galois.com:5025/pate/pate:refs-heads-master || \
             echo "No latest image found"
 
+      # Our self-hosted runners don't support buildx so we have to populate
+      # TARGETPLATFORM manually via build-arg to pass our check in the
+      # Dockerfile
       - name: Build Docker Image
         run: |
-          docker build . \
+          docker build --platform linux/amd64 --build-arg TARGETPLATFORM=linux/amd64 . \
             --cache-from artifactory.galois.com:5025/pate/pate:${GITHUB_REF//\//\-} \
             --cache-from artifactory.galois.com:5025/pate/pate:refs-heads-master \
             -t pate