diff --git a/binding-mri/binding-mri.cpp b/binding-mri/binding-mri.cpp
index a6d9685..a4f0960 100644
--- a/binding-mri/binding-mri.cpp
+++ b/binding-mri/binding-mri.cpp
@@ -585,7 +585,6 @@ static void mriBindingExecute()
 
 #if RUBY_API_VERSION_MAJOR == 1
 	ruby_init();
-	//ruby_options(argc, argv);
 #else
 	ruby_sysinit(&argc, &argv);
 	ruby_setup();
diff --git a/binding-mri/binding-util.cpp b/binding-mri/binding-util.cpp
index 6203ec8..1bc2b49 100644
--- a/binding-mri/binding-util.cpp
+++ b/binding-mri/binding-util.cpp
@@ -91,16 +91,16 @@ void
 raiseDisposedAccess(VALUE self)
 {
 #ifdef RUBY_LEGACY_VERSION
-// FIXME: raiseDisposedAccess not implemented
+	const char *klassName = rb_class2name(self);
 #else
 	const char *klassName = RTYPEDDATA_TYPE(self)->wrap_struct_name;
+#endif
 	char buf[32];
 
 	strncpy(buf, klassName, sizeof(buf));
 	buf[0] = tolower(buf[0]);
 
 	rb_raise(getRbData()->exc[RGSS], "disposed %s", buf);
-#endif
 }
 
 int
@@ -325,72 +325,120 @@ rb_get_args(int argc, VALUE *argv, const char *format, ...)
 }
 
 #if RUBY_API_VERSION_MAJOR == 1
-NORETURN(void rb_error_arity(int, int, int)) {
+NORETURN(void rb_error_arity(int, int, int))
+{
 	assert(false);
 }
+
 #if RUBY_API_VERSION_MINOR == 8
-// Functions providing Ruby 1.8 compatibililty
-VALUE rb_sprintf(const char* fmt, ...) {
-	va_list args;
-	va_start(args, fmt);
+/*
+Functions providing Ruby 1.8 compatibililty.
+All encoding related functions return dummy values because mkxp only uses them
+to retrieve the UTF-8 encoding.
+*/
+VALUE rb_sprintf_vararg(const char* fmt, va_list args) {
 	char buf[4096];
-	int const result = vsnprintf(buf, sizeof(buf), fmt, args);
-	va_end(args);
+	int result = vsnprintf(buf, sizeof(buf), fmt, args);
+
+	if (result < 0) {
+		buf[0] = '\0';
+	}
 
 	return rb_str_new2(buf);
 }
 
-VALUE rb_data_typed_object_alloc(VALUE klass, void *datap, const rb_data_type_t * rbType) {
-	return  rb_data_object_alloc(klass, 0, rbType->function.dmark, rbType->function.dfree);
+VALUE rb_sprintf(const char* fmt, ...)
+{
+	va_list args;
+	va_start(args, fmt);
+	VALUE val = rb_sprintf_vararg(fmt, args);
+	va_end(args);
+
+	return val;
 }
 
-void *rb_check_typeddata(VALUE v, const rb_data_type_t *) {
-// FIXME: rb_check_typeddata not implemented
-	return RTYPEDDATA_DATA(v);
+VALUE rb_data_typed_object_alloc(VALUE klass, void *datap, const rb_data_type_t *rbType)
+{
+	return rb_data_object_alloc(klass, 0, rbType->function.dmark, rbType->function.dfree);
 }
 
-VALUE rb_enc_str_new(const char* ch, long len, rb_encoding*) {
+void *rb_check_typeddata(VALUE value, const rb_data_type_t* typed)
+{
+// FIXME: Won't work because rb_typeddata_is_kind_of is not implemented
+	if (!rb_typeddata_is_kind_of(value, typed)) {
+		rb_raise(getRbData()->exc[RGSS],
+			"wrong data type %s (expected %s)", rb_class2name(value), typed->wrap_struct_name
+		);
+	}
+
+	return RTYPEDDATA_DATA(value);
+}
+
+VALUE rb_enc_str_new(const char* ch, long len, rb_encoding*)
+{
+	// Encoding is ignored
 	return rb_str_new(ch, len);
 }
 
-rb_encoding *rb_utf8_encoding(void) {
+rb_encoding *rb_utf8_encoding(void)
+{
+	// not relevant
 	return NULL;
 }
 
-void rb_enc_set_default_external(VALUE encoding) {
-	// no-op, assuming UTF-8
+void rb_enc_set_default_external(VALUE)
+{
+	// not relevant
 }
 
-VALUE rb_enc_from_encoding(rb_encoding *enc) {
+VALUE rb_enc_from_encoding(rb_encoding*)
+{
+	// not relevant
 	return Qnil;
 }
 
-VALUE rb_str_catf(VALUE, const char*, ...) {
-	return Qnil;
+VALUE rb_str_catf(VALUE value, const char* fmt, ...)
+{
+	va_list args;
+	va_start(args, fmt);
+	VALUE second = rb_sprintf_vararg(fmt, args);
+	va_end(args);
+
+	return rb_str_concat(value, second);
 }
 
-VALUE rb_errinfo(void) {
+VALUE rb_errinfo(void)
+{
 	return ruby_errinfo;
 }
 
-int rb_typeddata_is_kind_of(VALUE, const rb_data_type_t *) {
+int rb_typeddata_is_kind_of(VALUE value, const rb_data_type_t* typed)
+{
+// FIXME: rb_typeddata_is_kind_of not implemented
 	return 1;
 }
 
-VALUE rb_file_open_str(VALUE filename, const char* mode) {
+VALUE rb_file_open_str(VALUE filename, const char* mode)
+{
 	return rb_file_open(RB_OBJ_STRING(filename), mode);
 }
 
-VALUE rb_enc_associate_index(VALUE, int) {
+VALUE rb_enc_associate_index(VALUE, int)
+{
+	// not relevant
 	return Qnil;
 }
 
-int rb_utf8_encindex(void) {
+int rb_utf8_encindex(void)
+{
+	// not relevant
 	return 0;
 }
 
-VALUE rb_hash_lookup2(VALUE, VALUE, VALUE) {
-	return Qnil;
+VALUE rb_hash_lookup2(VALUE hash, VALUE key, VALUE def)
+{
+	VALUE v = rb_hash_lookup(hash, key);
+	return (v == Qnil) ? def : v;
 }
 #endif // RUBY_API_VERSION_MINOR == 8
-#endif // RUBY_API_VERSION_MAJOR == 1
\ No newline at end of file
+#endif // RUBY_API_VERSION_MAJOR == 1
diff --git a/binding-mri/filesystem-binding.cpp b/binding-mri/filesystem-binding.cpp
index 9a92c52..512ce4f 100644
--- a/binding-mri/filesystem-binding.cpp
+++ b/binding-mri/filesystem-binding.cpp
@@ -132,6 +132,7 @@ kernelLoadDataInt(const char *filename, bool rubyExc)
 	VALUE port = fileIntForPath(filename, rubyExc);
 
 	VALUE marsh = rb_const_get(rb_cObject, rb_intern("Marshal"));
+
 	// FIXME need to catch exceptions here with begin rescue
 	VALUE result = rb_funcall2(marsh, rb_intern("load"), 1, &port);