diff --git a/libraries/AP_Common/AP_MetaClass.h b/libraries/AP_Common/AP_MetaClass.h
index b46f4308d1..1025fad962 100644
--- a/libraries/AP_Common/AP_MetaClass.h
+++ b/libraries/AP_Common/AP_MetaClass.h
@@ -108,7 +108,7 @@ public:
     /// @return					An opaque handle
     ///
     Meta_handle meta_get_handle(void) const {
-        return ((Meta_handle)meta_type_id() << 16) | (uint16_t)this;
+        return ((Meta_handle)meta_type_id() << 16) | (uintptr_t)this;
     }
 
     /// Validates an AP_Meta_class handle.
@@ -134,7 +134,7 @@ public:
         // Note that this implies that we cannot deal with objects in ROM or EEPROM,
         // but the constructor wouldn't be able to populate a vtable pointer there anyway...
         //
-        if ((uint16_t)candidate >= (RAMEND - 2)) { // -2 to account for the type_id
+        if ((uintptr_t)candidate >= (RAMEND - 2)) { // -2 to account for the type_id
             return NULL;
         }
 
diff --git a/libraries/AP_Common/c++.cpp b/libraries/AP_Common/c++.cpp
index c1307ea13f..e2fc437a2f 100644
--- a/libraries/AP_Common/c++.cpp
+++ b/libraries/AP_Common/c++.cpp
@@ -78,10 +78,10 @@ int freeMemory()
 {
     int free_memory;
 
-    if ((int)__brkval == 0)
-        free_memory = ((int)&free_memory) - ((int)&__bss_end);
+    if ((intptr_t)__brkval == 0)
+        free_memory = ((intptr_t)&free_memory) - ((intptr_t)&__bss_end);
     else
-        free_memory = ((int)&free_memory) - ((int)__brkval);
+        free_memory = ((intptr_t)&free_memory) - ((intptr_t)__brkval);
 
     return free_memory;
 }