Index: src/OFString.m
==================================================================
--- src/OFString.m
+++ src/OFString.m
@@ -574,28 +574,34 @@
 			switch (characterLen) {
 			case 1:
 				string[i++] = buffer[0];
 				break;
 			case 2:
+				isUTF8 = YES;
+
 				length++;
 				string = [self resizeMemory: string
 						     toSize: length + 1];
 
 				memcpy(string + i, buffer, 2);
 				i += 2;
 
 				break;
 			case 3:
+				isUTF8 = YES;
+
 				length += 2;
 				string = [self resizeMemory: string
 						     toSize: length + 1];
 
 				memcpy(string + i, buffer, 3);
 				i += 3;
 
 				break;
 			case 4:
+				isUTF8 = YES;
+
 				length += 3;
 				string = [self resizeMemory: string
 						     toSize: length + 1];
 
 				memcpy(string + i, buffer, 4);