diff --git a/recipes/fuchsia/rerun.expected/1_core.json b/recipes/fuchsia/rerun.expected/1_core.json
new file mode 100644
index 0000000..8261072
--- /dev/null
+++ b/recipes/fuchsia/rerun.expected/1_core.json
@@ -0,0 +1,139 @@
+[
+  {
+    "cmd": [
+      "bb",
+      "batch",
+      "-host",
+      "cr-buildbucket.appspot.com"
+    ],
+    "infra_step": true,
+    "name": "buildbucket.search",
+    "stdin": "{\"requests\": [{\"searchBuilds\": {\"fields\": \"builds.*.builder,builds.*.createTime,builds.*.createdBy,builds.*.critical,builds.*.endTime,builds.*.id,builds.*.input,builds.*.number,builds.*.output,builds.*.startTime,builds.*.status,builds.*.updateTime\", \"pageSize\": 1, \"predicate\": {\"builder\": {\"bucket\": \"source-bucket\", \"builder\": \"source-builder\", \"project\": \"project\"}, \"status\": \"SUCCESS\"}}}]}",
+    "~followup_annotations": [
+      "@@@STEP_LOG_LINE@json.output@{@@@",
+      "@@@STEP_LOG_LINE@json.output@  \"responses\": [@@@",
+      "@@@STEP_LOG_LINE@json.output@    {@@@",
+      "@@@STEP_LOG_LINE@json.output@      \"searchBuilds\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@        \"builds\": [@@@",
+      "@@@STEP_LOG_LINE@json.output@          {@@@",
+      "@@@STEP_LOG_LINE@json.output@            \"builder\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@              \"bucket\": \"ci\", @@@",
+      "@@@STEP_LOG_LINE@json.output@              \"builder\": \"builder\", @@@",
+      "@@@STEP_LOG_LINE@json.output@              \"project\": \"project\"@@@",
+      "@@@STEP_LOG_LINE@json.output@            }, @@@",
+      "@@@STEP_LOG_LINE@json.output@            \"createTime\": \"2018-05-25T23:50:17Z\", @@@",
+      "@@@STEP_LOG_LINE@json.output@            \"createdBy\": \"user:luci-scheduler@appspot.gserviceaccount.com\", @@@",
+      "@@@STEP_LOG_LINE@json.output@            \"id\": \"8945511751514863184\", @@@",
+      "@@@STEP_LOG_LINE@json.output@            \"infra\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@              \"swarming\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@                \"priority\": 30@@@",
+      "@@@STEP_LOG_LINE@json.output@              }@@@",
+      "@@@STEP_LOG_LINE@json.output@            }, @@@",
+      "@@@STEP_LOG_LINE@json.output@            \"input\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@              \"gitilesCommit\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@                \"host\": \"chromium.googlesource.com\", @@@",
+      "@@@STEP_LOG_LINE@json.output@                \"id\": \"2d72510e447ab60a9728aeea2362d8be2cbd7789\", @@@",
+      "@@@STEP_LOG_LINE@json.output@                \"project\": \"project\", @@@",
+      "@@@STEP_LOG_LINE@json.output@                \"ref\": \"refs/heads/master\"@@@",
+      "@@@STEP_LOG_LINE@json.output@              }@@@",
+      "@@@STEP_LOG_LINE@json.output@            }, @@@",
+      "@@@STEP_LOG_LINE@json.output@            \"output\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@              \"properties\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@                \"child_build_id\": 123@@@",
+      "@@@STEP_LOG_LINE@json.output@              }@@@",
+      "@@@STEP_LOG_LINE@json.output@            }@@@",
+      "@@@STEP_LOG_LINE@json.output@          }@@@",
+      "@@@STEP_LOG_LINE@json.output@        ]@@@",
+      "@@@STEP_LOG_LINE@json.output@      }@@@",
+      "@@@STEP_LOG_LINE@json.output@    }@@@",
+      "@@@STEP_LOG_LINE@json.output@  ]@@@",
+      "@@@STEP_LOG_LINE@json.output@}@@@",
+      "@@@STEP_LOG_END@json.output@@@",
+      "@@@STEP_LOG_LINE@request@{@@@",
+      "@@@STEP_LOG_LINE@request@  \"requests\": [@@@",
+      "@@@STEP_LOG_LINE@request@    {@@@",
+      "@@@STEP_LOG_LINE@request@      \"searchBuilds\": {@@@",
+      "@@@STEP_LOG_LINE@request@        \"fields\": \"builds.*.builder,builds.*.createTime,builds.*.createdBy,builds.*.critical,builds.*.endTime,builds.*.id,builds.*.input,builds.*.number,builds.*.output,builds.*.startTime,builds.*.status,builds.*.updateTime\", @@@",
+      "@@@STEP_LOG_LINE@request@        \"pageSize\": 1, @@@",
+      "@@@STEP_LOG_LINE@request@        \"predicate\": {@@@",
+      "@@@STEP_LOG_LINE@request@          \"builder\": {@@@",
+      "@@@STEP_LOG_LINE@request@            \"bucket\": \"source-bucket\", @@@",
+      "@@@STEP_LOG_LINE@request@            \"builder\": \"source-builder\", @@@",
+      "@@@STEP_LOG_LINE@request@            \"project\": \"project\"@@@",
+      "@@@STEP_LOG_LINE@request@          }, @@@",
+      "@@@STEP_LOG_LINE@request@          \"status\": \"SUCCESS\"@@@",
+      "@@@STEP_LOG_LINE@request@        }@@@",
+      "@@@STEP_LOG_LINE@request@      }@@@",
+      "@@@STEP_LOG_LINE@request@    }@@@",
+      "@@@STEP_LOG_LINE@request@  ]@@@",
+      "@@@STEP_LOG_LINE@request@}@@@",
+      "@@@STEP_LOG_END@request@@@",
+      "@@@STEP_LINK@8945511751514863184@https://cr-buildbucket.appspot.com/build/8945511751514863184@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "bb",
+      "batch",
+      "-host",
+      "cr-buildbucket.appspot.com"
+    ],
+    "infra_step": true,
+    "name": "buildbucket.schedule",
+    "stdin": "{\"requests\": [{\"scheduleBuild\": {\"builder\": {\"bucket\": \"rerun\", \"builder\": \"source-builder-1-core\", \"project\": \"project\"}, \"experimental\": \"NO\", \"fields\": \"builder,createTime,createdBy,critical,endTime,id,input,number,output,startTime,status,updateTime\", \"gitilesCommit\": {\"host\": \"chromium.googlesource.com\", \"id\": \"2d72510e447ab60a9728aeea2362d8be2cbd7789\", \"project\": \"project\", \"ref\": \"refs/heads/master\"}, \"priority\": 30, \"properties\": {\"child_build_id\": 123}, \"requestId\": \"8945511751514863184-00000000-0000-0000-0000-000000001337\", \"tags\": [{\"key\": \"user_agent\", \"value\": \"recipe\"}]}}]}",
+    "~followup_annotations": [
+      "@@@STEP_LOG_LINE@json.output@{@@@",
+      "@@@STEP_LOG_LINE@json.output@  \"responses\": [@@@",
+      "@@@STEP_LOG_LINE@json.output@    {@@@",
+      "@@@STEP_LOG_LINE@json.output@      \"scheduleBuild\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@        \"builder\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@          \"bucket\": \"rerun\", @@@",
+      "@@@STEP_LOG_LINE@json.output@          \"builder\": \"source-builder-1-core\", @@@",
+      "@@@STEP_LOG_LINE@json.output@          \"project\": \"project\"@@@",
+      "@@@STEP_LOG_LINE@json.output@        }, @@@",
+      "@@@STEP_LOG_LINE@json.output@        \"id\": \"8922054662172514000\"@@@",
+      "@@@STEP_LOG_LINE@json.output@      }@@@",
+      "@@@STEP_LOG_LINE@json.output@    }@@@",
+      "@@@STEP_LOG_LINE@json.output@  ]@@@",
+      "@@@STEP_LOG_LINE@json.output@}@@@",
+      "@@@STEP_LOG_END@json.output@@@",
+      "@@@STEP_LOG_LINE@request@{@@@",
+      "@@@STEP_LOG_LINE@request@  \"requests\": [@@@",
+      "@@@STEP_LOG_LINE@request@    {@@@",
+      "@@@STEP_LOG_LINE@request@      \"scheduleBuild\": {@@@",
+      "@@@STEP_LOG_LINE@request@        \"builder\": {@@@",
+      "@@@STEP_LOG_LINE@request@          \"bucket\": \"rerun\", @@@",
+      "@@@STEP_LOG_LINE@request@          \"builder\": \"source-builder-1-core\", @@@",
+      "@@@STEP_LOG_LINE@request@          \"project\": \"project\"@@@",
+      "@@@STEP_LOG_LINE@request@        }, @@@",
+      "@@@STEP_LOG_LINE@request@        \"experimental\": \"NO\", @@@",
+      "@@@STEP_LOG_LINE@request@        \"fields\": \"builder,createTime,createdBy,critical,endTime,id,input,number,output,startTime,status,updateTime\", @@@",
+      "@@@STEP_LOG_LINE@request@        \"gitilesCommit\": {@@@",
+      "@@@STEP_LOG_LINE@request@          \"host\": \"chromium.googlesource.com\", @@@",
+      "@@@STEP_LOG_LINE@request@          \"id\": \"2d72510e447ab60a9728aeea2362d8be2cbd7789\", @@@",
+      "@@@STEP_LOG_LINE@request@          \"project\": \"project\", @@@",
+      "@@@STEP_LOG_LINE@request@          \"ref\": \"refs/heads/master\"@@@",
+      "@@@STEP_LOG_LINE@request@        }, @@@",
+      "@@@STEP_LOG_LINE@request@        \"priority\": 30, @@@",
+      "@@@STEP_LOG_LINE@request@        \"properties\": {@@@",
+      "@@@STEP_LOG_LINE@request@          \"child_build_id\": 123@@@",
+      "@@@STEP_LOG_LINE@request@        }, @@@",
+      "@@@STEP_LOG_LINE@request@        \"requestId\": \"8945511751514863184-00000000-0000-0000-0000-000000001337\", @@@",
+      "@@@STEP_LOG_LINE@request@        \"tags\": [@@@",
+      "@@@STEP_LOG_LINE@request@          {@@@",
+      "@@@STEP_LOG_LINE@request@            \"key\": \"user_agent\", @@@",
+      "@@@STEP_LOG_LINE@request@            \"value\": \"recipe\"@@@",
+      "@@@STEP_LOG_LINE@request@          }@@@",
+      "@@@STEP_LOG_LINE@request@        ]@@@",
+      "@@@STEP_LOG_LINE@request@      }@@@",
+      "@@@STEP_LOG_LINE@request@    }@@@",
+      "@@@STEP_LOG_LINE@request@  ]@@@",
+      "@@@STEP_LOG_LINE@request@}@@@",
+      "@@@STEP_LOG_END@request@@@",
+      "@@@STEP_LINK@8922054662172514000@https://cr-buildbucket.appspot.com/build/8922054662172514000@@@"
+    ]
+  },
+  {
+    "name": "$result"
+  }
+]
\ No newline at end of file
diff --git a/recipes/fuchsia/rerun.py b/recipes/fuchsia/rerun.py
index 7a799c6..7213ba6 100644
--- a/recipes/fuchsia/rerun.py
+++ b/recipes/fuchsia/rerun.py
@@ -14,9 +14,7 @@
 
 """
 
-from PB.go.chromium.org.luci.buildbucket.proto import build as build_pb2
 from PB.go.chromium.org.luci.buildbucket.proto import common as common_pb2
-from PB.go.chromium.org.luci.buildbucket.proto import rpc as rpc_pb2
 
 from recipe_engine.recipe_api import Property
 
@@ -45,10 +43,17 @@
   # Flaky builders are rarely successful, so we take any build.
   if source_builder.endswith('-flaky'):
     last_build_status = None
+
+  # TODO(fxb/44578): We'll no longer need this special case once we've reduced
+  # memory usage such that all rerun builders can run on 1-core machines.
+  original_builder = source_builder
+  one_core_suffix = '-1-core'
+  if original_builder.endswith(one_core_suffix):
+    original_builder = original_builder[:-len(one_core_suffix)]
   source_build = api.buildbucket_util.last_build(
       my_build.builder.project,
       source_bucket,
-      source_builder,
+      original_builder,
       status=last_build_status)
   if not source_build:
     raise api.step.InfraFailure(
@@ -80,3 +85,8 @@
   yield (api.status_check.test('success') + properties +
          api.buildbucket.simulated_search_results([source_build]) +
          api.buildbucket.ci_build(bucket='rerun'))
+
+  yield (api.status_check.test('1_core') + api.properties(
+      source_bucket='source-bucket', source_builder='source-builder-1-core') +
+         api.buildbucket.simulated_search_results([source_build]) +
+         api.buildbucket.ci_build(bucket='rerun'))