diff --git a/.github/workflows/arduino.yml b/.github/workflows/arduino.yml
index 5a2efa266..a6fbba1ba 100644
--- a/.github/workflows/arduino.yml
+++ b/.github/workflows/arduino.yml
@@ -6,6 +6,7 @@ on:
     branches: [ master, release/v8.* ]
 jobs:
   lint:
+    if: ${{ github.event_name != 'pull_request' || github.repository != github.event.pull_request.head.repo.full_name }}
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
diff --git a/.github/workflows/build_micropython.yml b/.github/workflows/build_micropython.yml
index a0d0230c0..dbad36c67 100644
--- a/.github/workflows/build_micropython.yml
+++ b/.github/workflows/build_micropython.yml
@@ -6,6 +6,7 @@ on:
 
 jobs:
   build:
+    if: ${{ github.event_name != 'pull_request' || github.repository != github.event.pull_request.head.repo.full_name }}
     name: Build ${{ matrix.port }} port
     runs-on: ubuntu-latest
     continue-on-error: true
diff --git a/.github/workflows/ccpp.yml b/.github/workflows/ccpp.yml
index 2574c05a1..37f46e5cf 100644
--- a/.github/workflows/ccpp.yml
+++ b/.github/workflows/ccpp.yml
@@ -8,6 +8,7 @@ on:
 
 jobs:
   build:
+    if: ${{ github.event_name != 'pull_request' || github.repository != github.event.pull_request.head.repo.full_name }}
     runs-on: ubuntu-latest
     strategy:
       matrix:
diff --git a/.github/workflows/check_conf.yml b/.github/workflows/check_conf.yml
index 34599d3f4..422237098 100644
--- a/.github/workflows/check_conf.yml
+++ b/.github/workflows/check_conf.yml
@@ -5,6 +5,7 @@ on:
 
 jobs:
   verify-conf-internal:
+    if: ${{ github.event_name != 'pull_request' || github.repository != github.event.pull_request.head.repo.full_name }}
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
diff --git a/.github/workflows/check_style.yml b/.github/workflows/check_style.yml
index b2944d365..b5cec3ef0 100644
--- a/.github/workflows/check_style.yml
+++ b/.github/workflows/check_style.yml
@@ -5,6 +5,7 @@ on:
 
 jobs:
   verify-formatting:
+    if: ${{ github.event_name != 'pull_request' || github.repository != github.event.pull_request.head.repo.full_name }}
     runs-on: ubuntu-latest
     steps:
       - name: Checkout