diff --git a/features/cellular/framework/device/CellularStateMachine.cpp b/features/cellular/framework/device/CellularStateMachine.cpp
index 25988de447..d56c7912da 100644
--- a/features/cellular/framework/device/CellularStateMachine.cpp
+++ b/features/cellular/framework/device/CellularStateMachine.cpp
@@ -153,7 +153,7 @@ bool CellularStateMachine::open_sim()
     }
 
     if (state == CellularDevice::SimStatePinNeeded) {
-        if (strlen(_sim_pin)) {
+        if (_sim_pin) {
             tr_info("Entering PIN to open SIM");
             _cb_data.error = _cellularDevice.set_pin(_sim_pin);
             if (_cb_data.error) {
@@ -428,13 +428,13 @@ void CellularStateMachine::state_sim_pin()
         }
 
         if (_network->is_active_context()) { // check if context was already activated
-            tr_debug("ACTIVE CONTEXT FOUND, skip registering.");
+            tr_debug("Active context found.");
             _network_status |= ACTIVE_PDP_CONTEXT;
         }
         CellularNetwork::AttachStatus status; // check if modem is already attached to a network
         if (_network->get_attach(status) == NSAPI_ERROR_OK && status == CellularNetwork::Attached) {
             _network_status |= ATTACHED_TO_NETWORK;
-            tr_debug("DEVICE IS ALREADY ATTACHED TO NETWORK, skip registering and attach.");
+            tr_debug("Cellular already attached.");
         }
         if (_plmn) {
             enter_to_state(STATE_MANUAL_REGISTERING_NETWORK);
diff --git a/features/cellular/framework/device/CellularStateMachine.h b/features/cellular/framework/device/CellularStateMachine.h
index c9d10e9f25..7b4e7656af 100644
--- a/features/cellular/framework/device/CellularStateMachine.h
+++ b/features/cellular/framework/device/CellularStateMachine.h
@@ -42,6 +42,7 @@ private:
     // friend of CellularDevice so that it's the only way to close/delete this class.
     friend class CellularDevice;
     friend class AT_CellularDevice;
+    friend class UT_CellularStateMachine; // for unit tests
     /** Constructor
      *
      * @param device    reference to CellularDevice
@@ -98,7 +99,7 @@ private:
      *  @param timeout      timeout array using seconds
      *  @param array_len    length of the array
      */
-    void set_retry_timeout_array(uint16_t timeout[], int array_len);
+    void set_retry_timeout_array(uint16_t *timeout, int array_len);
 
     /** Sets the operator plmn which is used when registering to a network specified by plmn. If plmn is not set then automatic
      *  registering is used when registering to a cellular network. Does not start any operations.