4 files changed, 10 insertions, 5 deletions
diff --git a/src/drivers/SpiMaster.cpp b/src/drivers/SpiMaster.cpp
index e2be5027..0d5bb83c 100644
--- a/src/drivers/SpiMaster.cpp
+++ b/src/drivers/SpiMaster.cpp
@@ -7,11 +7,14 @@
 using namespace Pinetime::Drivers;
 
 SpiMaster::SpiMaster(const SpiMaster::SpiModule spi, const SpiMaster::Parameters& params) : spi {spi}, params {params} {
-  mutex = xSemaphoreCreateBinary();
-  ASSERT(mutex != NULL);
 }
 
 bool SpiMaster::Init() {
+  if(mutex == nullptr) {
+    mutex = xSemaphoreCreateBinary();
+    ASSERT(mutex != nullptr);
+  }
+
   /* Configure GPIO pins used for pselsck, pselmosi, pselmiso and pselss for SPI0 */
   nrf_gpio_pin_set(params.pinSCK);
   nrf_gpio_cfg_output(params.pinSCK);
diff --git a/src/drivers/SpiMaster.h b/src/drivers/SpiMaster.h
index 5045369a..5ea624f2 100644
--- a/src/drivers/SpiMaster.h
+++ b/src/drivers/SpiMaster.h
@@ -59,7 +59,7 @@ namespace Pinetime {
       volatile uint32_t currentBufferAddr = 0;
       volatile size_t currentBufferSize = 0;
       volatile TaskHandle_t taskToNotify;
-      SemaphoreHandle_t mutex;
+      SemaphoreHandle_t mutex = nullptr;
     };
   }
 }
diff --git a/src/drivers/TwiMaster.cpp b/src/drivers/TwiMaster.cpp
index 7b6582dd..fc9edf81 100644
--- a/src/drivers/TwiMaster.cpp
+++ b/src/drivers/TwiMaster.cpp
@@ -9,10 +9,12 @@ using namespace Pinetime::Drivers;
 // TODO use DMA/IRQ
 
 TwiMaster::TwiMaster(const Modules module, const Parameters& params) : module {module}, params {params} {
-  mutex = xSemaphoreCreateBinary();
 }
 
 void TwiMaster::Init() {
+  if(mutex == nullptr)
+    mutex = xSemaphoreCreateBinary();
+  
   NRF_GPIO->PIN_CNF[params.pinScl] =
     ((uint32_t) GPIO_PIN_CNF_DIR_Input << GPIO_PIN_CNF_DIR_Pos) | ((uint32_t) GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos) |
     ((uint32_t) GPIO_PIN_CNF_PULL_Pullup << GPIO_PIN_CNF_PULL_Pos) | ((uint32_t) GPIO_PIN_CNF_DRIVE_S0D1 << GPIO_PIN_CNF_DRIVE_Pos) |
diff --git a/src/drivers/TwiMaster.h b/src/drivers/TwiMaster.h
index 1c0648a2..6175b99b 100644
--- a/src/drivers/TwiMaster.h
+++ b/src/drivers/TwiMaster.h
@@ -31,7 +31,7 @@ namespace Pinetime {
       ErrorCodes Write(uint8_t deviceAddress, const uint8_t* data, size_t size, bool stop);
       void FixHwFreezed();
       NRF_TWIM_Type* twiBaseAddress;
-      SemaphoreHandle_t mutex;
+      SemaphoreHandle_t mutex = nullptr;
       const Modules module;
       const Parameters params;
       static constexpr uint8_t maxDataSize {16};