diff --git a/TactilityKernel/include/tactility/module.h b/TactilityKernel/include/tactility/module.h
index 345a762c..910f29b4 100644
--- a/TactilityKernel/include/tactility/module.h
+++ b/TactilityKernel/include/tactility/module.h
@@ -118,6 +118,7 @@ error_t module_construct_add_start(struct Module* module);
 
 /**
  * @brief Check if the module is started.
+ * Can be used when module isn't constructed yet.
  * @param module module to check
  * @return true if the module is started, false otherwise
  */
diff --git a/TactilityKernel/source/module.cpp b/TactilityKernel/source/module.cpp
index 51200f43..5275709d 100644
--- a/TactilityKernel/source/module.cpp
+++ b/TactilityKernel/source/module.cpp
@@ -12,8 +12,8 @@ struct ModuleInternal {
 };
 
 struct ModuleLedger {
-    std::vector<struct Module*> modules;
-    struct Mutex mutex {};
+    std::vector<Module*> modules;
+    Mutex mutex {};
 
     ModuleLedger() { mutex_construct(&mutex); }
     ~ModuleLedger() { mutex_destruct(&mutex); }
@@ -23,36 +23,37 @@ static ModuleLedger ledger;
 
 extern "C" {
 
-error_t module_construct(struct Module* module) {
+error_t module_construct(Module* module) {
     module->internal = new (std::nothrow) ModuleInternal();
     if (module->internal == nullptr) return ERROR_OUT_OF_MEMORY;
     return ERROR_NONE;
 }
 
-error_t module_destruct(struct Module* module) {
+error_t module_destruct(Module* module) {
     delete static_cast<ModuleInternal*>(module->internal);
     module->internal = nullptr;
     return ERROR_NONE;
 }
 
-error_t module_add(struct Module* module) {
+error_t module_add(Module* module) {
     mutex_lock(&ledger.mutex);
     ledger.modules.push_back(module);
     mutex_unlock(&ledger.mutex);
     return ERROR_NONE;
 }
 
-error_t module_remove(struct Module* module) {
+error_t module_remove(Module* module) {
     mutex_lock(&ledger.mutex);
     ledger.modules.erase(std::remove(ledger.modules.begin(), ledger.modules.end(), module), ledger.modules.end());
     mutex_unlock(&ledger.mutex);
     return ERROR_NONE;
 }
 
-error_t module_start(struct Module* module) {
+error_t module_start(Module* module) {
     LOG_I(TAG, "start %s", module->name);
 
-    auto* internal = static_cast<ModuleInternal*>(module->internal);
+    auto* internal = module->internal;
+    if (internal == nullptr) return ERROR_INVALID_STATE;
     if (internal->started) return ERROR_NONE;
 
     error_t error = module->start();
@@ -61,13 +62,15 @@ error_t module_start(struct Module* module) {
 }
 
 bool module_is_started(struct Module* module) {
-    return static_cast<ModuleInternal*>(module->internal)->started;
+    auto* internal = module->internal;
+    return internal != nullptr && internal->started;
 }
 
 error_t module_stop(struct Module* module) {
     LOG_I(TAG, "stop %s", module->name);
 
-    auto* internal = static_cast<ModuleInternal*>(module->internal);
+    auto* internal = module->internal;
+    if (internal == nullptr) return ERROR_INVALID_STATE;
     if (!internal->started) return ERROR_NONE;
 
     error_t error = module->stop();