Index: src/wal.c
==================================================================
--- src/wal.c
+++ src/wal.c
@@ -3232,10 +3232,13 @@
 ** decreased at all.
 */
 int sqlite3WalSnapshotRecover(Wal *pWal){
   int rc;
 
+  /* Snapshots may not be used with wal2 mode databases. */
+  if( isWalMode2(pWal) ) return SQLITE_ERROR;
+
   assert( pWal->readLock>=0 );
   rc = walLockExclusive(pWal, WAL_CKPT_LOCK, 1);
   if( rc==SQLITE_OK ){
     volatile WalCkptInfo *pInfo = walCkptInfo(pWal);
     int szPage = (int)pWal->szPage;
@@ -3306,10 +3309,11 @@
   int cnt = 0;                    /* Number of TryBeginRead attempts */
 
 #ifdef SQLITE_ENABLE_SNAPSHOT
   int bChanged = 0;
   WalIndexHdr *pSnapshot = pWal->pSnapshot;
+  if( pSnapshot && isWalMode2(pWal) ) return SQLITE_ERROR;
   if( pSnapshot && memcmp(pSnapshot, &pWal->hdr, sizeof(WalIndexHdr))!=0 ){
     bChanged = 1;
   }
 #endif
 
@@ -4531,14 +4535,17 @@
 */
 int sqlite3WalSnapshotGet(Wal *pWal, sqlite3_snapshot **ppSnapshot){
   int rc = SQLITE_OK;
   WalIndexHdr *pRet;
   static const u32 aZero[4] = { 0, 0, 0, 0 };
+
+  /* Snapshots may not be used with wal2 mode databases. */
+  if( isWalMode2(pWal) ) return SQLITE_ERROR;
 
   assert( pWal->readLock>=0 && pWal->writeLock==0 );
 
-  if( memcmp(&pWal->hdr.aFrameCksum[0],aZero,16)==0 ){
+  if( memcmp(&pWal->hdr.aFrameCksum[0],aZero,8)==0 ){
     *ppSnapshot = 0;
     return SQLITE_ERROR;
   }
   pRet = (WalIndexHdr*)sqlite3_malloc(sizeof(WalIndexHdr));
   if( pRet==0 ){
@@ -4585,10 +4592,14 @@
 ** occurs (any value other than SQLITE_OK is returned), the CHECKPOINTER
 ** lock is released before returning.
 */
 int sqlite3WalSnapshotCheck(Wal *pWal, sqlite3_snapshot *pSnapshot){
   int rc;
+
+  /* Snapshots may not be used with wal2 mode databases. */
+  if( isWalMode2(pWal) ) return SQLITE_ERROR;
+
   rc = walLockShared(pWal, WAL_CKPT_LOCK);
   if( rc==SQLITE_OK ){
     WalIndexHdr *pNew = (WalIndexHdr*)pSnapshot;
     if( memcmp(pNew->aSalt, pWal->hdr.aSalt, sizeof(pWal->hdr.aSalt))
      || pNew->mxFrame<walCkptInfo(pWal)->nBackfillAttempted