diff --git a/beacon_chain/spec/presets/v0_12_2/mainnet.nim b/beacon_chain/spec/presets/v0_12_2/mainnet.nim
index a31f3c322..aff2b6aa8 100644
--- a/beacon_chain/spec/presets/v0_12_2/mainnet.nim
+++ b/beacon_chain/spec/presets/v0_12_2/mainnet.nim
@@ -151,6 +151,8 @@ const
 
   # Validators
   # ---------------------------------------------------------------
+  # https://github.com/ethereum/eth2.0-specs/blob/v0.12.2/configs/mainnet/phase0.yaml#L38
+  ETH1_FOLLOW_DISTANCE* {.intdefine.}: uint64 = 1024 # blocks ~ 4 hours
   TARGET_AGGREGATORS_PER_COMMITTEE*: uint64 = 16 # validators
   RANDOM_SUBNETS_PER_VALIDATOR*: uint64 = 1 # subnet
   EPOCHS_PER_RANDOM_SUBNET_SUBSCRIPTION*: uint64 = 256 # epochs ~ 27 hours
diff --git a/beacon_chain/spec/presets/v0_12_2/minimal.nim b/beacon_chain/spec/presets/v0_12_2/minimal.nim
index 780112c1d..5c5aaa1da 100644
--- a/beacon_chain/spec/presets/v0_12_2/minimal.nim
+++ b/beacon_chain/spec/presets/v0_12_2/minimal.nim
@@ -39,6 +39,9 @@ const
   # ---------------------------------------------------------------
   # https://github.com/ethereum/eth2.0-specs/blob/v0.12.2/configs/minimal/phase0.yaml#L61
 
+  # Changed
+  ETH1_FOLLOW_DISTANCE* {.intdefine.}: uint64 = 16 # blocks
+
   # Unchanged
   MIN_DEPOSIT_AMOUNT*: uint64 = 2'u64^0 * 10'u64^9
   MAX_EFFECTIVE_BALANCE*: uint64 = 2'u64^5 * 10'u64^9