diff --git a/core/src/main/java/org/bitcoinj/core/Block.java b/core/src/main/java/org/bitcoinj/core/Block.java
index 6422501f7..e0f4c3abd 100644
--- a/core/src/main/java/org/bitcoinj/core/Block.java
+++ b/core/src/main/java/org/bitcoinj/core/Block.java
@@ -32,7 +32,6 @@ import org.bitcoinj.crypto.ECKey;
 import org.bitcoinj.params.BitcoinNetworkParams;
 import org.bitcoinj.script.Script;
 import org.bitcoinj.script.ScriptBuilder;
-import org.bitcoinj.script.ScriptOpCodes;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -43,6 +42,7 @@ import java.io.OutputStream;
 import java.math.BigInteger;
 import java.nio.BufferUnderflowException;
 import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
 import java.time.Duration;
 import java.time.Instant;
 import java.time.temporal.ChronoUnit;
@@ -239,22 +239,19 @@ public class Block extends BaseMessage {
     }
 
     private static List<Transaction> genesisTransactions() {
-        Transaction tx = Transaction.coinbase(genesisTxInputScriptBytes);
-        tx.addOutput(new TransactionOutput(tx, FIFTY_COINS, genesisTxScriptPubKeyBytes));
+        byte[] messageBytes = GENESIS_MESSAGE.getBytes(StandardCharsets.US_ASCII);
+        Script scriptSig = // TODO find out what the pushdata(4) is supposed to mean
+                new ScriptBuilder().bigNum(STANDARD_MAX_DIFFICULTY_TARGET).bigNum(4).data(messageBytes).build();
+        Transaction tx = Transaction.coinbase(scriptSig.program());
+        tx.addOutput(new TransactionOutput(
+                tx, FIFTY_COINS, ScriptBuilder.createP2PKOutputScript(GENESIS_OUTPUT_PUBKEY).program()));
         return Collections.singletonList(tx);
     }
 
-    // A script containing the difficulty bits and the following message:
-    //
-    //   "The Times 03/Jan/2009 Chancellor on brink of second bailout for banks"
-    private static final byte[] genesisTxInputScriptBytes = ByteUtils.parseHex
-                ("04ffff001d0104455468652054696d65732030332f4a616e2f32303039204368616e63656c6c6f72206f6e206272696e6b206f66207365636f6e64206261696c6f757420666f722062616e6b73");
-
-    private static final byte[] genesisTxScriptPubKeyBytes = new ScriptBuilder()
-                .data(ByteUtils.parseHex("04678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4cef38c4f35504e51ec112de5c384df7ba0b8d578a4c702b6bf11d5f"))
-                .op(ScriptOpCodes.OP_CHECKSIG)
-                .build()
-                .program();
+    private static final String GENESIS_MESSAGE =
+            "The Times 03/Jan/2009 Chancellor on brink of second bailout for banks";
+    private static final byte[] GENESIS_OUTPUT_PUBKEY = ByteUtils.parseHex(
+            "04678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4cef38c4f35504e51ec112de5c384df7ba0b8d578a4c702b6bf11d5f");
 
     @Override
     public int messageSize() {