diff --git a/.gitmodules b/.gitmodules
index c4c957e..8696ec6 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,6 +1,6 @@
-[submodule "interface_lib/Fusion"]
-	path = interface_lib/Fusion
+[submodule "interface_lib/modules/Fusion"]
+	path = interface_lib/modules/Fusion
 	url = https://github.com/xioTechnologies/Fusion.git
-[submodule "interface_lib/hidapi"]
-	path = interface_lib/hidapi
+[submodule "interface_lib/modules/hidapi"]
+	path = interface_lib/modules/hidapi
 	url = https://github.com/libusb/hidapi.git
diff --git a/interface_lib/CMakeLists.txt b/interface_lib/CMakeLists.txt
index 20ad1c4..9692475 100644
--- a/interface_lib/CMakeLists.txt
+++ b/interface_lib/CMakeLists.txt
@@ -3,12 +3,10 @@ project(nrealAirLibrary C)
 
 set(CMAKE_C_STANDARD 17)
 
-add_subdirectory(hidapi)
 find_package(json-c REQUIRED CONFIG)
 
-add_subdirectory(Fusion/Fusion)
-set(FUSION_INCLUDE_DIR ${CMAKE_SOURCE_DIR}/interface_lib/Fusion)
-set(FUSION_LIBRARY Fusion)
+add_subdirectory(modules/hidapi)
+add_subdirectory(modules/Fusion/Fusion)
 
 add_library(
 		nrealAirLibrary
@@ -24,11 +22,13 @@ target_include_directories(nrealAirLibrary
 )
 
 target_include_directories(nrealAirLibrary
-		BEFORE PRIVATE ${FUSION_INCLUDE_DIR}
+		SYSTEM BEFORE PRIVATE 
+		${CMAKE_CURRENT_SOURCE_DIR}/modules/hidapi
+		${CMAKE_CURRENT_SOURCE_DIR}/modules/Fusion
 )
 
 target_link_libraries(nrealAirLibrary
-		PRIVATE hidapi::hidapi json-c::json-c ${FUSION_LIBRARY}
+		PRIVATE hidapi::hidapi json-c::json-c Fusion m
 )
 
 set(NREAL_AIR_INCLUDE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/include PARENT_SCOPE)
diff --git a/interface_lib/hidapi b/interface_lib/hidapi
deleted file mode 160000
index 09ab35f..0000000
--- a/interface_lib/hidapi
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 09ab35ffa9dce60a993f4e55cdeaf0952645f9b7
diff --git a/interface_lib/Fusion b/interface_lib/modules/Fusion
similarity index 100%
rename from interface_lib/Fusion
rename to interface_lib/modules/Fusion
diff --git a/interface_lib/modules/hidapi b/interface_lib/modules/hidapi
new file mode 160000
index 0000000..c19ae12
--- /dev/null
+++ b/interface_lib/modules/hidapi
@@ -0,0 +1 @@
+Subproject commit c19ae126d8856b55af34d64ee11641920475961c
diff --git a/interface_lib/src/device3.c b/interface_lib/src/device3.c
index 4d7af6e..2d80a8b 100644
--- a/interface_lib/src/device3.c
+++ b/interface_lib/src/device3.c
@@ -32,7 +32,7 @@
 #include <Fusion/Fusion.h>
 #include <json-c/json.h>
 
-#include <../hidapi/hidapi/hidapi.h>
+#include <hidapi/hidapi.h>
 
 #include "crc32.h"
 
@@ -235,7 +235,7 @@ device3_type* device3_open(device3_event_callback callback) {
 	
 	uint32_t calibration_len = 0;
 	if (recv_payload_msg(device, DEVICE3_MSG_GET_CAL_DATA_LENGTH, 4, (uint8_t*) &calibration_len)) {
-		char* calibration_data = malloc(calibration_len);
+		char* calibration_data = malloc(calibration_len + 1);
 		
 		uint32_t position = 0;
 		while (position < calibration_len) {
@@ -253,6 +253,8 @@ device3_type* device3_open(device3_event_callback callback) {
 			
 			position += next;
 		}
+
+		calibration_data[calibration_len] = '\0';
 		
 		struct json_tokener* tokener = json_tokener_new();
 		struct json_object* root = json_tokener_parse_ex(tokener, calibration_data, calibration_len);
diff --git a/interface_lib/src/device4.c b/interface_lib/src/device4.c
index 286c308..878b090 100644
--- a/interface_lib/src/device4.c
+++ b/interface_lib/src/device4.c
@@ -31,7 +31,7 @@
 #include <string.h>
 #include <time.h>
 
-#include <../hidapi/hidapi/hidapi.h>
+#include <hidapi/hidapi.h>
 
 #include "crc32.h"
 
@@ -111,16 +111,19 @@ static bool recv_payload_msg(device4_type* device, uint16_t msgid, uint8_t len,
 	}
 
 	if (packet.head != PACKET_HEAD) {
+		perror("ERROR: invalid payload received\n");
 		return false;
 	}
 	
 	if (packet.msgid != msgid) {
+		perror("ERROR: unexpected payload received\n");
 		return false;
 	}
-	
-	const uint8_t status = packet.data[0];
 
+	const uint8_t status = packet.data[0];
+	
 	if (status != 0) {
+		perror("ERROR: payload status failed\n");
 		return false;
 	}
 
@@ -153,6 +156,7 @@ static bool do_payload_action(device4_type* device, uint16_t msgid, uint8_t len,
 		attempts--;
 	}
 
+	perror("ERROR: payload status failed\n");
 	return false;
 }
 
@@ -483,6 +487,22 @@ bool device4_update_mcu_firmware(device4_type* device, const char* path) {
 		goto cleanup;
 	}
 
+	if (!send_payload_action(device, DEVICE4_MSG_R_ACTIVATION_TIME, 0, NULL)) {
+		perror("Requesting activation time failed!\n");
+		return device;
+	}
+
+	uint8_t activated;
+	if (!recv_payload_msg(device, DEVICE4_MSG_R_ACTIVATION_TIME, 1, &activated)) {
+		perror("Receiving activation time failed!\n");
+		return device;
+	}
+
+	if (!activated) {
+		perror("Device is not activated!\n");
+		goto jump_to_app;
+	}
+
 	size_t offset = 0;
 
 	while (offset < firmware_len) {
@@ -500,10 +520,12 @@ bool device4_update_mcu_firmware(device4_type* device, const char* path) {
 			msgid = DEVICE4_MSG_W_UPDATE_MCU_APP_FW_TRANSMIT;
 		}
 
-		if (!do_payload_action(device, msgid, len, firmware)) {
+		if (!do_payload_action(device, msgid, len, firmware + offset)) {
 			fprintf(stderr, "Failed sending firmware upload!\n");
 			goto jump_to_app;
 		}
+
+		offset += len;
 	}
 
 	printf("Finish upload!\n");