diff --git a/common/src/main/java/io/netty/util/AsciiString.java b/common/src/main/java/io/netty/util/AsciiString.java
index 056c55df07..9b1427923c 100644
--- a/common/src/main/java/io/netty/util/AsciiString.java
+++ b/common/src/main/java/io/netty/util/AsciiString.java
@@ -744,7 +744,7 @@ public final class AsciiString implements CharSequence, Comparable<CharSequence>
      */
     public int lastIndexOf(CharSequence string) {
         // Use count instead of count - 1 so lastIndexOf("") answers count
-        return lastIndexOf(string, length());
+        return lastIndexOf(string, length);
     }
 
     /**
@@ -759,23 +759,20 @@ public final class AsciiString implements CharSequence, Comparable<CharSequence>
      */
     public int lastIndexOf(CharSequence subString, int start) {
         final int subCount = subString.length();
+        start = Math.min(start, length - subCount);
         if (start < 0) {
-            start = 0;
-        }
-        if (subCount <= 0) {
-            return start < length ? start : length;
-        }
-        if (subCount > length - start) {
             return INDEX_NOT_FOUND;
         }
+        if (subCount == 0) {
+            return start;
+        }
 
         final char firstChar = subString.charAt(0);
         if (firstChar > MAX_CHAR_VALUE) {
             return INDEX_NOT_FOUND;
         }
         final byte firstCharAsByte = c2b0(firstChar);
-        final int end = offset + start;
-        for (int i = offset + length - subCount; i >= end; --i) {
+        for (int i = offset + start; i >= 0; --i) {
             if (value[i] == firstCharAsByte) {
                 int o1 = i, o2 = 0;
                 while (++o2 < subCount && b2c(value[++o1]) == subString.charAt(o2)) {
diff --git a/common/src/test/java/io/netty/util/AsciiStringCharacterTest.java b/common/src/test/java/io/netty/util/AsciiStringCharacterTest.java
index 76bd7dd72b..824979150c 100644
--- a/common/src/test/java/io/netty/util/AsciiStringCharacterTest.java
+++ b/common/src/test/java/io/netty/util/AsciiStringCharacterTest.java
@@ -361,15 +361,15 @@ public class AsciiStringCharacterTest {
     @Test
     public void testLastIndexOfCharSequence() {
         assertEquals(0, new AsciiString("abcd").lastIndexOf("abcd", 0));
-        assertEquals(0, new AsciiString("abcd").lastIndexOf("abc", 0));
-        assertEquals(1, new AsciiString("abcd").lastIndexOf("bcd", 0));
-        assertEquals(1, new AsciiString("abcd").lastIndexOf("bc", 0));
-        assertEquals(5, new AsciiString("abcdabcd").lastIndexOf("bcd", 0));
-        assertEquals(0, new AsciiString("abcd", 1, 2).lastIndexOf("bc", 0));
-        assertEquals(0, new AsciiString("abcd", 1, 3).lastIndexOf("bcd", 0));
-        assertEquals(1, new AsciiString("abcdabcd", 4, 4).lastIndexOf("bcd", 0));
+        assertEquals(0, new AsciiString("abcd").lastIndexOf("abc", 4));
+        assertEquals(1, new AsciiString("abcd").lastIndexOf("bcd", 4));
+        assertEquals(1, new AsciiString("abcd").lastIndexOf("bc", 4));
+        assertEquals(5, new AsciiString("abcdabcd").lastIndexOf("bcd", 10));
+        assertEquals(0, new AsciiString("abcd", 1, 2).lastIndexOf("bc", 2));
+        assertEquals(0, new AsciiString("abcd", 1, 3).lastIndexOf("bcd", 3));
+        assertEquals(1, new AsciiString("abcdabcd", 4, 4).lastIndexOf("bcd", 4));
         assertEquals(3, new AsciiString("012345").lastIndexOf("345", 3));
-        assertEquals(3, new AsciiString("012345").lastIndexOf("345", 0));
+        assertEquals(3, new AsciiString("012345").lastIndexOf("345", 6));
 
         // Test with empty string
         assertEquals(0, new AsciiString("abcd").lastIndexOf("", 0));
@@ -381,7 +381,7 @@ public class AsciiStringCharacterTest {
         assertEquals(-1, new AsciiString("abcdbc").lastIndexOf("bce", 0));
         assertEquals(-1, new AsciiString("abcd", 1, 3).lastIndexOf("abc", 0));
         assertEquals(-1, new AsciiString("abcd", 1, 2).lastIndexOf("bd", 0));
-        assertEquals(-1, new AsciiString("012345").lastIndexOf("345", 4));
+        assertEquals(-1, new AsciiString("012345").lastIndexOf("345", 2));
         assertEquals(-1, new AsciiString("012345").lastIndexOf("abc", 3));
         assertEquals(-1, new AsciiString("012345").lastIndexOf("abc", 0));
         assertEquals(-1, new AsciiString("012345").lastIndexOf("abcdefghi", 0));