diff --git a/beacon_node/beacon_chain/src/chain_config.rs b/beacon_node/beacon_chain/src/chain_config.rs
index 9921435313d..a74fdced1f6 100644
--- a/beacon_node/beacon_chain/src/chain_config.rs
+++ b/beacon_node/beacon_chain/src/chain_config.rs
@@ -73,6 +73,9 @@ pub struct ChainConfig {
     pub optimistic_finalized_sync: bool,
     /// The size of the shuffling cache,
     pub shuffling_cache_size: usize,
+    /// If using a weak-subjectivity sync, whether we should download blocks all the way back to
+    /// genesis.
+    pub genesis_backfill: bool,
     /// Whether to send payload attributes every slot, regardless of connected proposers.
     ///
     /// This is useful for block builders and testing.
@@ -106,6 +109,7 @@ impl Default for ChainConfig {
             // This value isn't actually read except in tests.
             optimistic_finalized_sync: true,
             shuffling_cache_size: crate::shuffling_cache::DEFAULT_CACHE_SIZE,
+            genesis_backfill: false,
             always_prepare_payload: false,
             enable_backfill_rate_limiting: true,
         }
diff --git a/beacon_node/beacon_chain/src/historical_blocks.rs b/beacon_node/beacon_chain/src/historical_blocks.rs
index 85a9ec8fb0b..657415ac8b5 100644
--- a/beacon_node/beacon_chain/src/historical_blocks.rs
+++ b/beacon_node/beacon_chain/src/historical_blocks.rs
@@ -193,13 +193,17 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
             oldest_block_parent: expected_block_root,
             ..anchor_info
         };
-        let backfill_complete = new_anchor.block_backfill_complete();
+        let backfill_complete = new_anchor.block_backfill_complete(self.genesis_backfill_slot);
         self.store
             .compare_and_set_anchor_info_with_write(Some(anchor_info), Some(new_anchor))?;
 
         // If backfill has completed and the chain is configured to reconstruct historic states,
         // send a message to the background migrator instructing it to begin reconstruction.
-        if backfill_complete && self.config.reconstruct_historic_states {
+        // This can only happen if we have backfilled all the way to genesis.
+        if backfill_complete
+            && self.genesis_backfill_slot == Slot::new(0)
+            && self.config.reconstruct_historic_states
+        {
             self.store_migrator.process_reconstruction();
         }
 
diff --git a/beacon_node/client/src/builder.rs b/beacon_node/client/src/builder.rs
index 329f0727542..39921115fc5 100644
--- a/beacon_node/client/src/builder.rs
+++ b/beacon_node/client/src/builder.rs
@@ -258,6 +258,12 @@ where
                 genesis_state_bytes,
             } => {
                 info!(context.log(), "Starting checkpoint sync");
+                if config.chain.genesis_backfill {
+                    info!(
+                        context.log(),
+                        "Blocks will downloaded all the way back to genesis"
+                    );
+                }
 
                 let anchor_state = BeaconState::from_ssz_bytes(&anchor_state_bytes, &spec)
                     .map_err(|e| format!("Unable to parse weak subj state SSZ: {:?}", e))?;
@@ -279,6 +285,12 @@ where
                     "Starting checkpoint sync";
                     "remote_url" => %url,
                 );
+                if config.chain.genesis_backfill {
+                    info!(
+                        context.log(),
+                        "Blocks will be downloaded all the way back to genesis"
+                    );
+                }
 
                 let remote = BeaconNodeHttpClient::new(
                     url,
diff --git a/beacon_node/client/src/notifier.rs b/beacon_node/client/src/notifier.rs
index 1105bc41f67..1ff469fe300 100644
--- a/beacon_node/client/src/notifier.rs
+++ b/beacon_node/client/src/notifier.rs
@@ -142,7 +142,8 @@ pub fn spawn_notifier<T: BeaconChainTypes>(
                             .get_anchor_info()
                             .map(|ai| ai.oldest_block_slot)
                         {
-                            sync_distance = current_anchor_slot;
+                            sync_distance = current_anchor_slot
+                                .saturating_sub(beacon_chain.genesis_backfill_slot);
                             speedo
                                 // For backfill sync use a fake slot which is the distance we've progressed from the starting `oldest_block_slot`.
                                 .observe(
@@ -207,14 +208,14 @@ pub fn spawn_notifier<T: BeaconChainTypes>(
                         "Downloading historical blocks";
                         "distance" => distance,
                         "speed" => sync_speed_pretty(speed),
-                        "est_time" => estimated_time_pretty(speedo.estimated_time_till_slot(original_anchor_slot.unwrap_or(current_slot))),
+                        "est_time" => estimated_time_pretty(speedo.estimated_time_till_slot(original_anchor_slot.unwrap_or(current_slot).saturating_sub(beacon_chain.genesis_backfill_slot))),
                     );
                 } else {
                     info!(
                         log,
                         "Downloading historical blocks";
                         "distance" => distance,
-                        "est_time" => estimated_time_pretty(speedo.estimated_time_till_slot(original_anchor_slot.unwrap_or(current_slot))),
+                        "est_time" => estimated_time_pretty(speedo.estimated_time_till_slot(original_anchor_slot.unwrap_or(current_slot).saturating_sub(beacon_chain.genesis_backfill_slot))),
                     );
                 }
             } else if !is_backfilling && last_backfill_log_slot.is_some() {
diff --git a/beacon_node/lighthouse_network/src/types/sync_state.rs b/beacon_node/lighthouse_network/src/types/sync_state.rs
index 5f09aec27a7..b82e63bd9c0 100644
--- a/beacon_node/lighthouse_network/src/types/sync_state.rs
+++ b/beacon_node/lighthouse_network/src/types/sync_state.rs
@@ -13,7 +13,7 @@ pub enum SyncState {
     /// The node is undertaking a backfill sync. This occurs when a user has specified a trusted
     /// state. The node first syncs "forward" by downloading blocks up to the current head as
     /// specified by its peers. Once completed, the node enters this sync state and attempts to
-    /// download all required historical blocks to complete its chain.
+    /// download all required historical blocks.
     BackFillSyncing { completed: usize, remaining: usize },
     /// The node has completed syncing a finalized chain and is in the process of re-evaluating
     /// which sync state to progress to.
diff --git a/beacon_node/src/cli.rs b/beacon_node/src/cli.rs
index ca20ba352f8..a15a420a226 100644
--- a/beacon_node/src/cli.rs
+++ b/beacon_node/src/cli.rs
@@ -254,6 +254,12 @@ pub fn cli_app<'a, 'b>() -> App<'a, 'b> {
                 .help("One or more comma-delimited trusted peer ids which always have the highest score according to the peer scoring system.")
                 .takes_value(true),
         )
+        .arg(
+            Arg::with_name("genesis-backfill")
+                .long("genesis-backfill")
+                .help("Attempts to download blocks all the way back to genesis when checkpoint syncing.")
+                .takes_value(false),
+        )
         .arg(
             Arg::with_name("enable-private-discovery")
                 .long("enable-private-discovery")
@@ -873,7 +879,7 @@ pub fn cli_app<'a, 'b>() -> App<'a, 'b> {
         .arg(
             Arg::with_name("reconstruct-historic-states")
                 .long("reconstruct-historic-states")
-                .help("After a checkpoint sync, reconstruct historic states in the database.")
+                .help("After a checkpoint sync, reconstruct historic states in the database. This requires syncing all the way back to genesis.")
                 .takes_value(false)
         )
         .arg(
diff --git a/beacon_node/src/config.rs b/beacon_node/src/config.rs
index 272ac9b3310..e2863e98388 100644
--- a/beacon_node/src/config.rs
+++ b/beacon_node/src/config.rs
@@ -545,6 +545,7 @@ pub fn get_config<E: EthSpec>(
 
     if cli_args.is_present("reconstruct-historic-states") {
         client_config.chain.reconstruct_historic_states = true;
+        client_config.chain.genesis_backfill = true;
     }
 
     let raw_graffiti = if let Some(graffiti) = cli_args.value_of("graffiti") {
@@ -817,6 +818,9 @@ pub fn get_config<E: EthSpec>(
     client_config.chain.optimistic_finalized_sync =
         !cli_args.is_present("disable-optimistic-finalized-sync");
 
+    if cli_args.is_present("genesis-backfill") {
+        client_config.chain.genesis_backfill = true;
+    }
     // Payload selection configs
     if cli_args.is_present("always-prefer-builder-payload") {
         client_config.always_prefer_builder_payload = true;
diff --git a/beacon_node/store/src/metadata.rs b/beacon_node/store/src/metadata.rs
index 6d27f0cc85a..4a58674936a 100644
--- a/beacon_node/store/src/metadata.rs
+++ b/beacon_node/store/src/metadata.rs
@@ -100,8 +100,10 @@ pub struct AnchorInfo {
 
 impl AnchorInfo {
     /// Returns true if the block backfill has completed.
-    pub fn block_backfill_complete(&self) -> bool {
-        self.oldest_block_slot == 0
+    /// This is a comparison between the oldest block slot and the target backfill slot (which is
+    /// likely to be the closest WSP).
+    pub fn block_backfill_complete(&self, target_slot: Slot) -> bool {
+        self.oldest_block_slot <= target_slot
     }
 }
 
diff --git a/lighthouse/tests/beacon_node.rs b/lighthouse/tests/beacon_node.rs
index 8b924b5a511..59f5f9ee57b 100644
--- a/lighthouse/tests/beacon_node.rs
+++ b/lighthouse/tests/beacon_node.rs
@@ -345,6 +345,23 @@ fn trusted_peers_flag() {
         });
 }
 
+#[test]
+fn genesis_backfill_flag() {
+    CommandLineTest::new()
+        .flag("genesis-backfill", None)
+        .run_with_zero_port()
+        .with_config(|config| assert_eq!(config.chain.genesis_backfill, true));
+}
+
+/// The genesis backfill flag should be enabled if historic states flag is set.
+#[test]
+fn genesis_backfill_with_historic_flag() {
+    CommandLineTest::new()
+        .flag("reconstruct-historic-states", None)
+        .run_with_zero_port()
+        .with_config(|config| assert_eq!(config.chain.genesis_backfill, true));
+}
+
 #[test]
 fn always_prefer_builder_payload_flag() {
     CommandLineTest::new()