diff --git a/hal/src/fsfw_hal/linux/uio/UioMapper.cpp b/hal/src/fsfw_hal/linux/uio/UioMapper.cpp
index bdf126bf..546fb2cc 100644
--- a/hal/src/fsfw_hal/linux/uio/UioMapper.cpp
+++ b/hal/src/fsfw_hal/linux/uio/UioMapper.cpp
@@ -63,7 +63,7 @@ ReturnValue_t UioMapper::getMapSize(size_t* size) {
 #endif
     return HasReturnvaluesIF::RETURN_FAILED;
   }
-  items = sscanf(hexstring, "%x", size);
+  items = sscanf(hexstring, "%lx", size);
   if (items != 1) {
 #if FSFW_CPP_OSTREAM_ENABLED == 1
     sif::warning << "UioMapper::getMapSize: Failed with error code " << errno << "to convert "