diff --git a/src/allmydata/immutable/checker.py b/src/allmydata/immutable/checker.py
index 0268d8d..4e6e609 100644
--- a/src/allmydata/immutable/checker.py
+++ b/src/allmydata/immutable/checker.py
@@ -612,19 +612,22 @@ class Checker(log.PrefixingLogMixin):
             return d
         d.addCallback(_got_ueb)
 
-        def _discard_result(r):
-            assert isinstance(r, str), r
-            # to free up the RAM
-            return None
         def _get_blocks(vrbp):
-            ds = []
-            for blocknum in range(veup.num_segments):
+            def _discard_result(r):
+                assert isinstance(r, str), r
+                # to free up the RAM
+                return None
+            def _get_block(ign, blocknum):
                 db = vrbp.get_block(blocknum)
                 db.addCallback(_discard_result)
-                ds.append(db)
-            # this gatherResults will fire once every block of this share has
-            # been downloaded and verified, or else it will errback.
-            return deferredutil.gatherResults(ds)
+                return db
+            dbs = defer.succeed(None)
+            for blocknum in range(veup.num_segments):
+                dbs.addCallback(_get_block, blocknum)
+            # The Deferred we return will fire after every block of this
+            # share has been downloaded and verified successfully, or else it
+            # will errback as soon as the first error is observed.
+            return dbs
         d.addCallback(_get_blocks)
 
         # if none of those errbacked, the blocks (and the hashes above them)