diff --git a/fsfw b/fsfw
index 83d9dbc0..8ee26f81 160000
--- a/fsfw
+++ b/fsfw
@@ -1 +1 @@
-Subproject commit 83d9dbc052109c0b1a0c2be72e3fb3015a9abdd7
+Subproject commit 8ee26f81f9449e28566a8d34fbb3454cfd1da01c
diff --git a/linux/boardtest/LibgpiodTest.cpp b/linux/boardtest/LibgpiodTest.cpp
index 0c5ebe2a..1c8fec5e 100644
--- a/linux/boardtest/LibgpiodTest.cpp
+++ b/linux/boardtest/LibgpiodTest.cpp
@@ -19,18 +19,18 @@ LibgpiodTest::LibgpiodTest(object_id_t objectId, object_id_t gpioIfobjectId, Gpi
 LibgpiodTest::~LibgpiodTest() {}
 
 ReturnValue_t LibgpiodTest::performPeriodicAction() {
-  int gpioState;
+  gpio::Levels gpioState;
   ReturnValue_t result;
 
   switch (testCase) {
     case (TestCases::READ): {
-      result = gpioInterface->readGpio(gpioIds::TEST_ID_0, &gpioState);
+      result = gpioInterface->readGpio(gpioIds::TEST_ID_0, gpioState);
       if (result != RETURN_OK) {
         sif::warning << "LibgpiodTest::performPeriodicAction: Failed to read gpio " << std::endl;
         return RETURN_FAILED;
       } else {
-        sif::debug << "LibgpiodTest::performPeriodicAction: MIO 0 state = " << gpioState
-                   << std::endl;
+        sif::debug << "LibgpiodTest::performPeriodicAction: MIO 0 state = " <<
+            static_cast<int>(gpioState) << std::endl;
       }
       break;
     }
@@ -38,19 +38,19 @@ ReturnValue_t LibgpiodTest::performPeriodicAction() {
       break;
     }
     case (TestCases::BLINK): {
-      result = gpioInterface->readGpio(gpioIds::TEST_ID_0, &gpioState);
+      result = gpioInterface->readGpio(gpioIds::TEST_ID_0, gpioState);
       if (result != HasReturnvaluesIF::RETURN_OK) {
         sif::warning << "LibgpiodTest::performPeriodicAction: Failed to read gpio " << std::endl;
         return RETURN_FAILED;
       }
-      if (gpioState == 1) {
+      if (gpioState == gpio::Levels::HIGH) {
         result = gpioInterface->pullLow(gpioIds::TEST_ID_0);
         if (result != HasReturnvaluesIF::RETURN_OK) {
           sif::warning << "LibgpiodTest::performPeriodicAction: Could not pull GPIO low!"
                        << std::endl;
           return HasReturnvaluesIF::RETURN_FAILED;
         }
-      } else if (gpioState == 0) {
+      } else if (gpioState == gpio::Levels::LOW) {
         result = gpioInterface->pullHigh(gpioIds::TEST_ID_0);
         if (result != HasReturnvaluesIF::RETURN_OK) {
           sif::warning << "LibgpiodTest::performPeriodicAction: Could not pull GPIO high!"
@@ -72,7 +72,7 @@ ReturnValue_t LibgpiodTest::performPeriodicAction() {
 }
 
 ReturnValue_t LibgpiodTest::performOneShotAction() {
-  int gpioState;
+  gpio::Levels gpioState;
   ReturnValue_t result;
 
   switch (testCase) {
@@ -93,8 +93,8 @@ ReturnValue_t LibgpiodTest::performOneShotAction() {
                      << std::endl;
         return HasReturnvaluesIF::RETURN_OK;
       }
-      result = gpioInterface->readGpio(gpioIds::TEST_ID_1, &gpioState);
-      if (result == HasReturnvaluesIF::RETURN_OK and gpioState == 1) {
+      result = gpioInterface->readGpio(gpioIds::TEST_ID_1, gpioState);
+      if (result == HasReturnvaluesIF::RETURN_OK and gpioState == gpio::Levels::HIGH) {
         sif::info << "LibgpiodTest::performOneShotAction: "
                      "GPIO state read successfully and is high"
                   << std::endl;
@@ -110,8 +110,8 @@ ReturnValue_t LibgpiodTest::performOneShotAction() {
                      "GPIO pulled low successfully for loopback test"
                   << std::endl;
       }
-      result = gpioInterface->readGpio(gpioIds::TEST_ID_1, &gpioState);
-      if (result == HasReturnvaluesIF::RETURN_OK and gpioState == 0) {
+      result = gpioInterface->readGpio(gpioIds::TEST_ID_1, gpioState);
+      if (result == HasReturnvaluesIF::RETURN_OK and gpioState == gpio::Levels::LOW) {
         sif::info << "LibgpiodTest::performOneShotAction: "
                      "GPIO state read successfully and is low"
                   << std::endl;
diff --git a/linux/obc/PapbVcInterface.cpp b/linux/obc/PapbVcInterface.cpp
index 5636975a..643104d7 100644
--- a/linux/obc/PapbVcInterface.cpp
+++ b/linux/obc/PapbVcInterface.cpp
@@ -42,17 +42,17 @@ void PapbVcInterface::startPacketTransfer() { *vcBaseReg = CONFIG_START; }
 void PapbVcInterface::endPacketTransfer() { *vcBaseReg = CONFIG_END; }
 
 ReturnValue_t PapbVcInterface::pollPapbBusySignal() {
-  int papbBusyState = 0;
+  gpio::Levels papbBusyState = gpio::Levels::LOW;
   ReturnValue_t result = RETURN_OK;
 
   /** Check if PAPB interface is ready to receive data */
-  result = gpioComIF->readGpio(papbBusyId, &papbBusyState);
+  result = gpioComIF->readGpio(papbBusyId, papbBusyState);
   if (result != RETURN_OK) {
     sif::warning << "PapbVcInterface::pollPapbBusySignal: Failed to read papb busy signal"
                  << std::endl;
     return RETURN_FAILED;
   }
-  if (!papbBusyState) {
+  if (papbBusyState == gpio::Levels::LOW) {
     sif::warning << "PapbVcInterface::pollPapbBusySignal: PAPB busy" << std::endl;
     return PAPB_BUSY;
   }
@@ -62,9 +62,9 @@ ReturnValue_t PapbVcInterface::pollPapbBusySignal() {
 
 void PapbVcInterface::isVcInterfaceBufferEmpty() {
   ReturnValue_t result = RETURN_OK;
-  int papbEmptyState = 1;
+  gpio::Levels papbEmptyState = gpio::Levels::HIGH;
 
-  result = gpioComIF->readGpio(papbEmptyId, &papbEmptyState);
+  result = gpioComIF->readGpio(papbEmptyId, papbEmptyState);
 
   if (result != RETURN_OK) {
     sif::warning << "PapbVcInterface::isVcInterfaceBufferEmpty: Failed to read papb empty signal"
@@ -72,7 +72,7 @@ void PapbVcInterface::isVcInterfaceBufferEmpty() {
     return;
   }
 
-  if (papbEmptyState == 1) {
+  if (papbEmptyState == gpio::Levels::HIGH) {
     sif::debug << "PapbVcInterface::isVcInterfaceBufferEmpty: Buffer is empty" << std::endl;
   } else {
     sif::debug << "PapbVcInterface::isVcInterfaceBufferEmpty: Buffer is not empty" << std::endl;