diff --git a/sim/drivers/SpiMaster.cpp b/sim/drivers/SpiMaster.cpp
index 92e7ab2..e9d9473 100644
--- a/sim/drivers/SpiMaster.cpp
+++ b/sim/drivers/SpiMaster.cpp
@@ -176,7 +176,7 @@ void SpiMaster::OnStartedEvent() {
 //  spiBaseAddress->EVENTS_END = 0;
 //}
 
-bool SpiMaster::Write(uint8_t pinCsn, const uint8_t* data, size_t size) {
+bool SpiMaster::Write(uint8_t pinCsn, const uint8_t* data, size_t size, const std::function<void()>& preTransactionHook) {
 //  if (data == nullptr)
 //    return false;
 //  auto ok = xSemaphoreTake(mutex, portMAX_DELAY);
diff --git a/sim/drivers/SpiMaster.h b/sim/drivers/SpiMaster.h
index 14ba2d2..4e53492 100644
--- a/sim/drivers/SpiMaster.h
+++ b/sim/drivers/SpiMaster.h
@@ -1,6 +1,7 @@
 #pragma once
 #include <cstddef>
 #include <cstdint>
+#include <functional>
 
 #include <FreeRTOS.h>
 //#include <semphr.h>
@@ -30,7 +31,7 @@ namespace Pinetime {
       SpiMaster& operator=(SpiMaster&&) = delete;
 
       bool Init();
-      bool Write(uint8_t pinCsn, const uint8_t* data, size_t size);
+      bool Write(uint8_t pinCsn, const uint8_t* data, size_t size, const std::function<void()>& preTransactionHook);
       bool Read(uint8_t pinCsn, uint8_t* cmd, size_t cmdSize, uint8_t* data, size_t dataSize);
 
       bool WriteCmdAndBuffer(uint8_t pinCsn, const uint8_t* cmd, size_t cmdSize, const uint8_t* data, size_t dataSize);