diff --git a/.github/workflows/run-tests.yml b/.github/workflows/run-tests.yml
index 5bb3aaee736..711b5f321b6 100644
--- a/.github/workflows/run-tests.yml
+++ b/.github/workflows/run-tests.yml
@@ -99,5 +99,7 @@ jobs:
         working-directory: ports/zephyr-cp/tools/bsim
       - name: Build native_nrf5340bsim
         run: make -C ports/zephyr-cp -j2 BOARD=native_nrf5340bsim
+      - name: Build native_nrf54lm20bsim
+        run: make -C ports/zephyr-cp -j2 BOARD=native_nrf54lm20bsim
       - name: Run Zephyr tests
         run: make -C ports/zephyr-cp test
diff --git a/ports/zephyr-cp/tests/bsim/test_bsim_ble_advertising.py b/ports/zephyr-cp/tests/bsim/test_bsim_ble_advertising.py
index 27fa78a5b7f..c8450e2af9f 100644
--- a/ports/zephyr-cp/tests/bsim/test_bsim_ble_advertising.py
+++ b/ports/zephyr-cp/tests/bsim/test_bsim_ble_advertising.py
@@ -128,6 +128,7 @@
 
 @pytest.mark.zephyr_sample("tests/bsim/samples/observer")
 @pytest.mark.circuitpy_drive({"code.py": BSIM_ADV_CODE})
+@pytest.mark.duration(60)
 def test_bsim_advertise_and_scan(bsim_phy, circuitpython, zephyr_sample):
     """Advertise from CircuitPython and verify Zephyr observer sees traffic."""
     observer = zephyr_sample
diff --git a/ports/zephyr-cp/tests/bsim/test_bsim_ble_peripheral.py b/ports/zephyr-cp/tests/bsim/test_bsim_ble_peripheral.py
index a8eb2612b40..ff99b789f0c 100644
--- a/ports/zephyr-cp/tests/bsim/test_bsim_ble_peripheral.py
+++ b/ports/zephyr-cp/tests/bsim/test_bsim_ble_peripheral.py
@@ -95,7 +95,7 @@ def test_bsim_peripheral_zephyr_central(bsim_phy, circuitpython, zephyr_sample):
     assert "Disconnected:" in central_output
 
 
-@pytest.mark.duration(14)
+@pytest.mark.duration(20)
 @pytest.mark.circuitpy_drive({"code.py": BSIM_PERIPHERAL_CODE})
 @pytest.mark.circuitpy_drive({"code.py": BSIM_CENTRAL_CODE})
 def test_bsim_peripheral_cp_central(bsim_phy, circuitpython1, circuitpython2):