Index: src/runtime/ObjFWRT.h
==================================================================
--- src/runtime/ObjFWRT.h
+++ src/runtime/ObjFWRT.h
@@ -242,15 +242,14 @@
     void *_Nullable bytes);
 extern void *_Nullable objc_destructInstance(id _Nullable object);
 extern void *_Null_unspecified objc_autoreleasePoolPush(void);
 extern void objc_autoreleasePoolPop(void *_Null_unspecified pool);
 extern id _Nullable _objc_rootAutorelease(id _Nullable object);
-extern int_fast8_t objc_registerTaggedPointerClass(Class _Nonnull class);
+extern int objc_registerTaggedPointerClass(Class _Nonnull class);
 extern Class _Nullable object_getTaggedPointerClass(id _Nonnull object);
 extern uintptr_t object_getTaggedPointerValue(id _Nonnull object);
-extern id _Nullable objc_createTaggedPointer(uint_fast8_t class,
-    uintptr_t value);
+extern id _Nullable objc_createTaggedPointer(int class, uintptr_t value);
 
 /*
  * Used by the compiler, but can also be called manually.
  *
  * These declarations are also required to prevent Clang's implicit

Index: src/runtime/amiga-glue.m
==================================================================
--- src/runtime/amiga-glue.m
+++ src/runtime/amiga-glue.m
@@ -798,11 +798,11 @@
 	M68K_ARG(struct objc_hashtable *, table, a0)
 
 	objc_hashtable_free(table);
 }
 
-int_fast8_t
+int
 glue_objc_registerTaggedPointerClass PPC_PARAMS(Class class)
 {
 	M68K_ARG(Class, class, a0)
 
 	return objc_registerTaggedPointerClass(class);
@@ -823,12 +823,12 @@
 
 	return object_getTaggedPointerValue(object);
 }
 
 id
-glue_objc_createTaggedPointer PPC_PARAMS(uint_fast8_t class, uintptr_t value)
+glue_objc_createTaggedPointer PPC_PARAMS(int class, uintptr_t value)
 {
-	M68K_ARG(uint_fast8_t, class, d0)
+	M68K_ARG(int, class, d0)
 	M68K_ARG(uintptr_t, value, d1)
 
 	return objc_createTaggedPointer(class, value);
 }

Index: src/runtime/amiga-library.m
==================================================================
--- src/runtime/amiga-library.m
+++ src/runtime/amiga-library.m
@@ -145,11 +145,11 @@
 extern struct objc_hashtable *glue_objc_hashtable_new(void);
 extern void glue_objc_hashtable_set(void);
 extern void *glue_objc_hashtable_get(void);
 extern void glue_objc_hashtable_delete(void);
 extern void glue_objc_hashtable_free(void);
-extern int_fast8_t glue_objc_registerTaggedPointerClass(void);
+extern int glue_objc_registerTaggedPointerClass(void);
 extern Class _Nullable glue_object_getTaggedPointerClass(void);
 extern uintptr_t glue_object_getTaggedPointerValue(void);
 extern id _Nullable glue_objc_createTaggedPointer(void);
 
 #ifdef OF_MORPHOS

Index: src/runtime/amigaos3.sfd
==================================================================
--- src/runtime/amigaos3.sfd
+++ src/runtime/amigaos3.sfd
@@ -88,10 +88,10 @@
 void glue_objc_hashtable_set(struct objc_hashtable *_Nonnull table, const void *_Nonnull key, const void *_Nonnull object)(a0,a1,a2)
 void *_Nullable glue_objc_hashtable_get(struct objc_hashtable *_Nonnull table, const void *_Nonnull key)(a0,a1)
 void glue_objc_hashtable_delete(struct objc_hashtable *_Nonnull table, const void *_Nonnull key)(a0,a1)
 void glue_objc_hashtable_free(struct objc_hashtable *_Nonnull table)(a0)
 * Public functions again
-int_fast8_t glue_objc_registerTaggedPointerClass(Class _Nonnull class_)(a0)
+int glue_objc_registerTaggedPointerClass(Class _Nonnull class_)(a0)
 Class _Nullable glue_object_getTaggedPointerClass(id _Nonnull object)(a0)
 uintptr_t glue_object_getTaggedPointerValue(id _Nonnull object)(a0)
-id _Nullable glue_objc_createTaggedPointer(uint_fast8_t class_, uintptr_t value)(d0,d1)
+id _Nullable glue_objc_createTaggedPointer(int class_, uintptr_t value)(d0,d1)
 ==end

Index: src/runtime/linklib/linklib.m
==================================================================
--- src/runtime/linklib/linklib.m
+++ src/runtime/linklib/linklib.m
@@ -706,10 +706,28 @@
 objc_hashtable_free(struct objc_hashtable *table)
 {
 	glue_objc_hashtable_free(table);
 }
 
-extern int_fast8_t objc_registerTaggedPointerClass(Class _Nonnull class);
-extern Class _Nullable object_getTaggedPointerClass(id _Nonnull object);
-extern uintptr_t object_getTaggedPointerValue(id _Nonnull object);
-extern id _Nullable objc_createTaggedPointer(uint_fast8_t class,
-    uintptr_t value);
+int
+objc_registerTaggedPointerClass(Class class)
+{
+	return glue_objc_registerTaggedPointerClass(class);
+}
+
+Class
+object_getTaggedPointerClass(id object)
+{
+	return glue_object_getTaggedPointerClass(object);
+}
+
+uintptr_t
+object_getTaggedPointerValue(id object)
+{
+	return glue_object_getTaggedPointerValue(object);
+}
+
+id
+objc_createTaggedPointer(int class, uintptr_t value)
+{
+	return objc_createTaggedPointer(class, value);
+}

Index: src/runtime/morphos-clib.h
==================================================================
--- src/runtime/morphos-clib.h
+++ src/runtime/morphos-clib.h
@@ -83,9 +83,9 @@
 void glue_objc_hashtable_set(struct objc_hashtable *, const void *, const void *);
 void *glue_objc_hashtable_get(struct objc_hashtable *, const void *);
 void glue_objc_hashtable_delete(struct objc_hashtable *, const void *);
 void glue_objc_hashtable_free(struct objc_hashtable *);
 /* Public functions again */
-int_fast8_t glue_objc_registerTaggedPointerClass(Class);
+int glue_objc_registerTaggedPointerClass(Class);
 Class _Nullable glue_object_getTaggedPointerClass(id);
 uintptr_t glue_object_getTaggedPointerValue(id);
-id glue_objc_createTaggedPointer(uint_fast8_t, uintptr_t);
+id glue_objc_createTaggedPointer(int, uintptr_t);

Index: src/runtime/tagged-pointer.m
==================================================================
--- src/runtime/tagged-pointer.m
+++ src/runtime/tagged-pointer.m
@@ -21,16 +21,16 @@
 
 #define TAGGED_POINTER_BITS 4
 #define NUM_TAGGED_POINTER_CLASSES (1 << (TAGGED_POINTER_BITS - 1))
 
 Class objc_tagged_pointer_classes[NUM_TAGGED_POINTER_CLASSES];
-static uint_fast8_t taggedPointerClassesCount;
+static int taggedPointerClassesCount;
 
-int_fast8_t
+int
 objc_registerTaggedPointerClass(Class class)
 {
-	uint_fast8_t i;
+	int i;
 
 	objc_global_mutex_lock();
 
 	if (taggedPointerClassesCount == NUM_TAGGED_POINTER_CLASSES) {
 		objc_global_mutex_unlock();
@@ -68,15 +68,15 @@
 
 	return pointer;
 }
 
 id
-objc_createTaggedPointer(uint_fast8_t class, uintptr_t value)
+objc_createTaggedPointer(int class, uintptr_t value)
 {
 	uintptr_t pointer;
 
-	if (class >= NUM_TAGGED_POINTER_CLASSES)
+	if (class < 0 || class >= NUM_TAGGED_POINTER_CLASSES)
 		return nil;
 
 	if (value > (UINTPTR_MAX >> TAGGED_POINTER_BITS))
 		return nil;