diff --git a/eras/byron/ledger/impl/CHANGELOG.md b/eras/byron/ledger/impl/CHANGELOG.md
index 9e7c30cb635..2b16a34fd7d 100644
--- a/eras/byron/ledger/impl/CHANGELOG.md
+++ b/eras/byron/ledger/impl/CHANGELOG.md
@@ -1,8 +1,8 @@
 # Revision history for `cardano-ledger-byron`
 
-## 1.0.1.1
+## 1.0.2.0
 
-*
+* `force` `startTime` in the evaluation of genesis-data. #4574
 
 ## 1.0.1.0
 
diff --git a/eras/byron/ledger/impl/cardano-ledger-byron.cabal b/eras/byron/ledger/impl/cardano-ledger-byron.cabal
index 8888092d5c4..f3b09d2ac41 100644
--- a/eras/byron/ledger/impl/cardano-ledger-byron.cabal
+++ b/eras/byron/ledger/impl/cardano-ledger-byron.cabal
@@ -1,6 +1,6 @@
 cabal-version:      3.0
 name:               cardano-ledger-byron
-version:            1.0.1.0
+version:            1.0.2.0
 license:            Apache-2.0
 maintainer:         operations@iohk.io
 author:             IOHK
diff --git a/eras/byron/ledger/impl/src/Cardano/Chain/Genesis/Data.hs b/eras/byron/ledger/impl/src/Cardano/Chain/Genesis/Data.hs
index 9e9e880bab8..2dc8d24dc06 100644
--- a/eras/byron/ledger/impl/src/Cardano/Chain/Genesis/Data.hs
+++ b/eras/byron/ledger/impl/src/Cardano/Chain/Genesis/Data.hs
@@ -93,7 +93,7 @@ instance MonadError SchemaError m => FromJSON m GenesisData where
     GenesisData
       <$> fromJSField obj "bootStakeholders"
       <*> fromJSField obj "heavyDelegation"
-      <*> fromJSField obj "startTime"
+      <*> (force <$> fromJSField obj "startTime")
       <*> fromJSField obj "nonAvvmBalances"
       <*> fromJSField obj "blockVersionData"
       -- The above is called blockVersionData for backwards compatibility with