diff --git a/firmware/console/binary/tunerstudio_io.cpp b/firmware/console/binary/tunerstudio_io.cpp
index 5928ccf165..caa8e96342 100644
--- a/firmware/console/binary/tunerstudio_io.cpp
+++ b/firmware/console/binary/tunerstudio_io.cpp
@@ -149,13 +149,15 @@ bool stopTsPort(ts_channel_s *tsChannel) {
 }
 
 #if EFI_UNIT_TEST
-void sr5WriteData(ts_channel_s *tsChannel, const uint8_t * buffer, int size) {
+int sr5TestWriteDataIndex = 0;
+uint8_t st5TestBuffer[16000];
 
+void sr5WriteData(ts_channel_s *tsChannel, const uint8_t * buffer, int size) {
+	memcpy(&st5TestBuffer[sr5TestWriteDataIndex], buffer, size);
+	sr5TestWriteDataIndex += size;
 }
 #endif // EFI_UNIT_TEST
 
-
-
 #if EFI_PROD_CODE || EFI_SIMULATOR
 void sr5WriteData(ts_channel_s *tsChannel, const uint8_t * buffer, int size) {
         efiAssertVoid(CUSTOM_ERR_6570, getCurrentRemainingStack() > 64, "tunerStudioWriteData");
diff --git a/unit_tests/tests/test_tunerstudio.cpp b/unit_tests/tests/test_tunerstudio.cpp
new file mode 100644
index 0000000000..f9a5a897e5
--- /dev/null
+++ b/unit_tests/tests/test_tunerstudio.cpp
@@ -0,0 +1,33 @@
+#include "engine_test_helper.h"
+#include "tunerstudio_io.h"
+
+extern int sr5TestWriteDataIndex;
+extern uint8_t st5TestBuffer[16000];
+
+TEST(binary, testWriteCrc) {
+	sr5TestWriteDataIndex = 0;
+
+#define CODE 2
+#define PAYLOAD "123"
+#define SIZE strlen(PAYLOAD)
+
+	sr5WriteCrcPacket(nullptr, CODE, (const uint8_t * )PAYLOAD, SIZE);
+	ASSERT_EQ(sr5TestWriteDataIndex, SIZE + 7);
+
+	// todo: proper uint16 comparison
+	ASSERT_EQ(st5TestBuffer[0], 0);
+	ASSERT_EQ(st5TestBuffer[1], SIZE + 1);
+
+	ASSERT_EQ(st5TestBuffer[2], CODE);
+
+	ASSERT_EQ(memcmp(&st5TestBuffer[3], PAYLOAD, SIZE), 0);
+
+
+	// todo: proper uint32 comparison
+	ASSERT_EQ(st5TestBuffer[6], 252);
+	ASSERT_EQ(st5TestBuffer[7], 68);
+	ASSERT_EQ(st5TestBuffer[8], 173);
+	ASSERT_EQ(st5TestBuffer[9], 87);
+
+
+}
diff --git a/unit_tests/tests/tests.mk b/unit_tests/tests/tests.mk
index 1d41fd6150..4242c66f35 100644
--- a/unit_tests/tests/tests.mk
+++ b/unit_tests/tests/tests.mk
@@ -31,6 +31,7 @@ TESTS_SRC_CPP = \
 	tests/test_fuel_map.cpp \
 	tests/test_fuel_wall_wetting.cpp \
 	tests/test_one_cylinder_logic.cpp \
+	tests/test_tunerstudio.cpp \
 	tests/test_pwm_generator.cpp \
 	tests/test_logic_expression.cpp \
 	tests/test_signal_executor.cpp \