diff --git a/manifest b/manifest
index 1cbd91987d..bb1d336591 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C A\sbetter\s(smaller\sand\sfaster)\ssolution\sto\sticket\s[4374860b29383380].
-D 2020-02-17T19:25:07.592
+C Convert\sinvalid\ssurrogates\sto\s0xfffd\swhen\stranslating\sUTF.
+D 2020-02-17T23:08:16.564
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -600,7 +600,7 @@ F src/treeview.c 438c1000587b33faba35e87596bebcf7f40638d98f33781cdd9e04711b18b09
 F src/trigger.c a40d50e88bd3355f1d2a73f0a3b2d6b42eae26ca4219001b82ef0d064439badc
 F src/update.c 3eb778c42155d944377a4ee5e440b04520f07094804ed6ce63d2528f619614d9
 F src/upsert.c 2920de71b20f04fe25eb00b655d086f0ba60ea133c59d7fa3325c49838818e78
-F src/utf.c 736ff76753236ffbc8b5b939f5e0607f28aeaa7c780b3a56b419228f0a81c87b
+F src/utf.c 95fb6e03a5ca679045c5adccd05380f0addccabef5911abddcb06af069500ab7
 F src/util.c a285c1e026907b69fa2592bd05047a565a1d8a1aef2b73c924b6a8ffe772871a
 F src/vacuum.c 813b510ba887fee6492bcb11f2bf77d7eb58b232b83649136372e0a2fc17f4b9
 F src/vdbe.c 15cae95de3c1301747f7ee17a70046772741e7e630b6d5554c685b613798b8e8
@@ -1439,7 +1439,7 @@ F test/tkt-385a5b56b9.test 5204a7cba0e28c99df0acbf95af5e1af4d32965a7a14de6eccebf
 F test/tkt-38cb5df375.test f3cc8671f1eb604d4ae9cf886ed4366bec656678
 F test/tkt-3998683a16.test 6d1d04d551ed1704eb3396ca87bb9ccc8c5c1eb7
 F test/tkt-3a77c9714e.test 90e3e8455ee945a4076d4c44062b8845708af24a880355328fe7008f2047c9f0
-F test/tkt-3fe897352e.test 27e26eb0f1811aeba4d65aba43a4c52e99da5e70
+F test/tkt-3fe897352e.test 6849fde0a87165ff83f54f5047af7c743d72af26908fadb90174f3294450b3f4
 F test/tkt-4a03edc4c8.test 91c0e135888cdc3d4eea82406a44b05c8c1648d0
 F test/tkt-4c86b126f2.test cbcc611becd0396890169ab23102dd70048bbc9a
 F test/tkt-4dd95f6943.test 3d0ce415d2ee15d3d564121960016b9c7be79407
@@ -1858,7 +1858,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 9d0d4ab95dc0c56e053c2924ed322a9ea7b25439e6f74599f706905a1994e454
-R 1c052b7cdf4947664b7043564b643ac3
+P abc473fb8fb999005dc79a360e34f97b3b25429decf1820dd2afa5c19577753d
+R 4bf2952c1b8e70d0751661faff1674f3
 U drh
-Z e960557a43b001a47933dacf8bc1d10e
+Z 268df0dffaa8fc33ed45d27c33b3bdad
diff --git a/manifest.uuid b/manifest.uuid
index 26c2328b51..5af135d1b8 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-abc473fb8fb999005dc79a360e34f97b3b25429decf1820dd2afa5c19577753d
\ No newline at end of file
+7fab1393c2b22b1f3b159b631e06e7e0d3900850ee249c38e4d3cdd0aacf637e
\ No newline at end of file
diff --git a/src/utf.c b/src/utf.c
index f5fb3ef347..f6c8e79e50 100644
--- a/src/utf.c
+++ b/src/utf.c
@@ -105,26 +105,6 @@ static const unsigned char sqlite3Utf8Trans1[] = {
   }                                                                 \
 }
 
-#define READ_UTF16LE(zIn, TERM, c){                                   \
-  c = (*zIn++);                                                       \
-  c += ((*zIn++)<<8);                                                 \
-  if( c>=0xD800 && c<0xE000 && TERM ){                                \
-    int c2 = (*zIn++);                                                \
-    c2 += ((*zIn++)<<8);                                              \
-    c = (c2&0x03FF) + ((c&0x003F)<<10) + (((c&0x03C0)+0x0040)<<10);   \
-  }                                                                   \
-}
-
-#define READ_UTF16BE(zIn, TERM, c){                                   \
-  c = ((*zIn++)<<8);                                                  \
-  c += (*zIn++);                                                      \
-  if( c>=0xD800 && c<0xE000 && TERM ){                                \
-    int c2 = ((*zIn++)<<8);                                           \
-    c2 += (*zIn++);                                                   \
-    c = (c2&0x03FF) + ((c&0x003F)<<10) + (((c&0x03C0)+0x0040)<<10);   \
-  }                                                                   \
-}
-
 /*
 ** Translate a single UTF-8 character.  Return the unicode value.
 **
@@ -301,13 +281,43 @@ SQLITE_NOINLINE int sqlite3VdbeMemTranslate(Mem *pMem, u8 desiredEnc){
     if( pMem->enc==SQLITE_UTF16LE ){
       /* UTF-16 Little-endian -> UTF-8 */
       while( zIn<zTerm ){
-        READ_UTF16LE(zIn, zIn<zTerm, c); 
+        c = *(zIn++);
+        c += (*(zIn++))<<8;
+        if( c>=0xd800 && c<0xe000 ){
+          if( c>=0xdc00 || zIn>=zTerm ){
+            c = 0xfffd;
+          }else{
+            int c2 = *(zIn++);
+            c2 += (*(zIn++))<<8;
+            if( c2<0xdc00 || c2>=0xe000 ){
+              zIn -= 2;
+              c = 0xfffd;
+            }else{
+              c = ((c&0x3ff)<<10) + (c2&0x3ff) + 0x10000;
+            }
+          }
+        }
         WRITE_UTF8(z, c);
       }
     }else{
       /* UTF-16 Big-endian -> UTF-8 */
       while( zIn<zTerm ){
-        READ_UTF16BE(zIn, zIn<zTerm, c); 
+        c = (*(zIn++))<<8;
+        c += *(zIn++);
+        if( c>=0xd800 && c<0xe000 ){
+          if( c>=0xdc00 || zIn>=zTerm ){
+            c = 0xfffd;
+          }else{
+            int c2 = (*(zIn++))<<8;
+            c2 += *(zIn++);
+            if( c2<0xdc00 || c2>=0xe000 ){
+              zIn -= 2;
+              c = 0xfffd;
+            }else{
+              c = ((c&0x3ff)<<10) + (c2&0x3ff) + 0x10000;
+            }
+          }
+        }
         WRITE_UTF8(z, c);
       }
     }
@@ -466,18 +476,15 @@ int sqlite3Utf16ByteLen(const void *zIn, int nChar){
   unsigned char const *z = zIn;
   int n = 0;
   
-  if( SQLITE_UTF16NATIVE==SQLITE_UTF16BE ){
-    while( n<nChar ){
-      READ_UTF16BE(z, 1, c);
-      n++;
-    }
-  }else{
-    while( n<nChar ){
-      READ_UTF16LE(z, 1, c);
-      n++;
-    }
+  if( SQLITE_UTF16NATIVE==SQLITE_UTF16LE ) z++;
+  while( n<nChar ){
+    c = z[0];
+    z += 2;
+    if( c>=0xd8 && c<0xdc && z[0]>=0xdc && z[0]<0xe0 ) z += 2;
+    n++;
   }
-  return (int)(z-(unsigned char const *)zIn);
+  return (int)(z-(unsigned char const *)zIn) 
+              - (SQLITE_UTF16NATIVE==SQLITE_UTF16LE);
 }
 
 #if defined(SQLITE_TEST)
@@ -507,30 +514,6 @@ void sqlite3UtfSelfTest(void){
     assert( c==t );
     assert( (z-zBuf)==n );
   }
-  for(i=0; i<0x00110000; i++){
-    if( i>=0xD800 && i<0xE000 ) continue;
-    z = zBuf;
-    WRITE_UTF16LE(z, i);
-    n = (int)(z-zBuf);
-    assert( n>0 && n<=4 );
-    z[0] = 0;
-    z = zBuf;
-    READ_UTF16LE(z, 1, c);
-    assert( c==i );
-    assert( (z-zBuf)==n );
-  }
-  for(i=0; i<0x00110000; i++){
-    if( i>=0xD800 && i<0xE000 ) continue;
-    z = zBuf;
-    WRITE_UTF16BE(z, i);
-    n = (int)(z-zBuf);
-    assert( n>0 && n<=4 );
-    z[0] = 0;
-    z = zBuf;
-    READ_UTF16BE(z, 1, c);
-    assert( c==i );
-    assert( (z-zBuf)==n );
-  }
 }
 #endif /* SQLITE_TEST */
 #endif /* SQLITE_OMIT_UTF16 */
diff --git a/test/tkt-3fe897352e.test b/test/tkt-3fe897352e.test
index bc2b2033e7..fa70ac7658 100644
--- a/test/tkt-3fe897352e.test
+++ b/test/tkt-3fe897352e.test
@@ -33,28 +33,28 @@ do_test tkt-3fe89-1.1 {
     INSERT INTO t1 VALUES(hex_to_utf16be('D800'));
     SELECT hex(x) FROM t1;
   }
-} {EDA080}
+} {EFBFBD}
 do_test tkt-3fe89-1.2 {
   db eval {
     DELETE FROM t1;
     INSERT INTO t1 VALUES(hex_to_utf16le('00D8'));
     SELECT hex(x) FROM t1;
   }
-} {EDA080}
+} {EFBFBD}
 do_test tkt-3fe89-1.3 {
   db eval {
     DELETE FROM t1;
     INSERT INTO t1 VALUES(hex_to_utf16be('DFFF'));
     SELECT hex(x) FROM t1;
   }
-} {EDBFBF}
+} {EFBFBD}
 do_test tkt-3fe89-1.4 {
   db eval {
     DELETE FROM t1;
     INSERT INTO t1 VALUES(hex_to_utf16le('FFDF'));
     SELECT hex(x) FROM t1;
   }
-} {EDBFBF}
+} {EFBFBD}
 
 
 finish_test