diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 53829d9fa..8c4a440d2 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -31,6 +31,13 @@ jobs:
   #     runtime-ref: ${{ github.ref }}
   #     compiler-ref: ${{ needs.fetch-lf.outputs.ref }}
 
+  lf-default-zephyr:
+    needs: fetch-lf
+    uses: lf-lang/lingua-franca/.github/workflows/c-zephyr-tests.yml@master
+    with:
+      runtime-ref: ${{ github.ref }}
+      compiler-ref: ${{ needs.fetch-lf.outputs.ref }}
+
   lf-default:
     needs: fetch-lf
     uses: lf-lang/lingua-franca/.github/workflows/c-tests.yml@master
diff --git a/core/platform/lf_zephyr_support.c b/core/platform/lf_zephyr_support.c
index a14598a7f..66763fbc8 100644
--- a/core/platform/lf_zephyr_support.c
+++ b/core/platform/lf_zephyr_support.c
@@ -47,6 +47,7 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 // Keep track of overflows to keep clocks monotonic
 static int64_t _lf_timer_epoch_duration_nsec;
+static int64_t _lf_timer_epoch_duration_usec;
 static volatile int64_t _lf_timer_last_epoch_nsec = 0;
 
 #if defined(LF_ZEPHYR_CLOCK_HI_RES)
@@ -108,9 +109,11 @@ void lf_initialize_clock() {
         while(1) {};
     }
 
-    // Calculate the duration of an epoch
+    // Calculate the duration of an epoch. Compute both
+    //  nsec and usec now at boot to avoid these computations later
     counter_max_ticks = counter_get_max_top_value(_lf_counter_dev);
-    _lf_timer_epoch_duration_nsec = counter_ticks_to_us(_lf_counter_dev, counter_max_ticks) * 1000LL;
+    _lf_timer_epoch_duration_usec = counter_ticks_to_us(_lf_counter_dev, counter_max_ticks);
+    _lf_timer_epoch_duration_nsec = _lf_timer_epoch_duration_usec * 1000LL;
     
     // Set the max_top value to be the maximum
     counter_max_ticks = counter_get_max_top_value(_lf_counter_dev);
@@ -137,8 +140,10 @@ void lf_initialize_clock() {
     LF_PRINT_LOG("Using Low resolution zephyr kernel clock");
     LF_PRINT_LOG("Kernel Clock has frequency of %u Hz\n", CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC);
     _lf_timer_last_epoch_nsec = 0;
-    // Compute the duration of an 
+    // Compute the duration of an epoch. Compute both
+    //  nsec and usec now at boot to avoid these computations later
     _lf_timer_epoch_duration_nsec = ((1LL << 32) * SECONDS(1))/CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC;
+    _lf_timer_epoch_duration_usec = _lf_timer_epoch_duration_nsec/1000;
     #endif
 }   
 
diff --git a/include/core/platform/lf_zephyr_support.h b/include/core/platform/lf_zephyr_support.h
index 7baa70571..e446bdf71 100644
--- a/include/core/platform/lf_zephyr_support.h
+++ b/include/core/platform/lf_zephyr_support.h
@@ -62,7 +62,6 @@ typedef int64_t _interval_t;
 typedef uint32_t _microstep_t;
 
 #ifdef LF_THREADED
-#warning "Threaded support on Zephyr is still experimental"
 
 typedef struct k_mutex _lf_mutex_t;
 typedef struct k_condvar _lf_cond_t;