Index: src/OFString+JSONParsing.m
==================================================================
--- src/OFString+JSONParsing.m
+++ src/OFString+JSONParsing.m
@@ -135,13 +135,10 @@
 			ret |= c + 10 - 'A';
 		else
 			return 0xFFFF;
 	}
 
-	if (ret == 0)
-		return 0xFFFF;
-
 	return ret;
 }
 
 static inline OFString *
 parseString(const char **pointer, const char *stop, size_t *line)

Index: tests/OFJSONTests.m
==================================================================
--- tests/OFJSONTests.m
+++ tests/OFJSONTests.m
@@ -27,11 +27,11 @@
 	OFDictionary *_dictionary;
 }
 @end
 
 static OFString *string = @"{\"f\\0oo\"\t:'b\\na\\r', \"x\":/*foo*/ [.5\r,0xF,"
-    @"null//bar\n,\"foo\",false]}";
+    @"null//bar\n,\"fo\\u0000o\",false]}";
 
 @implementation OFJSONTests
 - (void)setUp
 {
 	[super setUp];
@@ -40,11 +40,11 @@
 	    @"f\0oo", @"b\na\r",
 	    @"x", [OFArray arrayWithObjects:
 		[OFNumber numberWithFloat: .5f],
 		[OFNumber numberWithInt: 0xF],
 		[OFNull null],
-		@"foo",
+		@"fo\0o",
 		[OFNumber numberWithBool: false],
 		nil],
 	    nil];
 }
 
@@ -61,11 +61,12 @@
 }
 
 - (void)testJSONRepresentation
 {
 	OTAssert(_dictionary.JSONRepresentation,
-	    @"{\"f\\u0000oo\":\"b\\na\\r\",\"x\":[0.5,15,null,\"foo\",false]}");
+	    @"{\"f\\u0000oo\":\"b\\na\\r\",\"x\":[0.5,15,null,\"fo\\u0000o\","
+	    @"false]}");
 }
 
 - (void)testSortedJSONRepresentation
 {
 	OTAssertEqualObjects(
@@ -78,18 +79,18 @@
 - (void)testPrettyJSONRepresentation
 {
 	OTAssertEqualObjects([_dictionary JSONRepresentationWithOptions:
 	    OFJSONRepresentationOptionPretty],
 	    @"{\n\t\"f\\u0000oo\": \"b\\na\\r\",\n\t\"x\": [\n\t\t0.5,\n\t\t15,"
-	    @"\n\t\tnull,\n\t\t\"foo\",\n\t\tfalse\n\t]\n}");
+	    @"\n\t\tnull,\n\t\t\"fo\\u0000o\",\n\t\tfalse\n\t]\n}");
 }
 
 - (void)testJSON5Representation
 {
 	OTAssertEqualObjects([_dictionary JSONRepresentationWithOptions:
 	    OFJSONRepresentationOptionJSON5],
-	    @"{\"f\\0oo\":\"b\\\na\\r\",x:[0.5,15,null,\"foo\",false]}");
+	    @"{\"f\\0oo\":\"b\\\na\\r\",x:[0.5,15,null,\"fo\\0o\",false]}");
 }
 
 - (void)testObjectByParsingJSONFailsWithInvalidJSON
 {
 	OTAssertThrowsSpecific([@"{" objectByParsingJSON],