diff --git a/common/htlc_tx.c b/common/htlc_tx.c
index 5be4b47f2..7427b2e15 100644
--- a/common/htlc_tx.c
+++ b/common/htlc_tx.c
@@ -4,24 +4,21 @@
 #include <common/htlc_tx.h>
 #include <common/keyset.h>
 
-static struct bitcoin_tx *htlc_tx(const tal_t *ctx,
-				  const struct chainparams *chainparams,
-				  const struct bitcoin_outpoint *commit,
-				  const u8 *commit_wscript,
-				  struct amount_msat msat,
-				  u16 to_self_delay,
-				  const struct pubkey *revocation_pubkey,
-				  const struct pubkey *local_delayedkey,
-				  struct amount_sat htlc_fee,
-				  u32 locktime,
-				  bool option_anchor_outputs)
+/* Low-level tx creator: used when onchaind has done most of the work! */
+struct bitcoin_tx *htlc_tx(const tal_t *ctx,
+			   const struct chainparams *chainparams,
+			   const struct bitcoin_outpoint *commit,
+			   const u8 *commit_wscript,
+			   struct amount_sat amount,
+			   const u8 *htlc_tx_wscript,
+			   struct amount_sat htlc_fee,
+			   u32 locktime,
+			   bool option_anchor_outputs)
 {
 	/* BOLT #3:
 	 * * locktime: `0` for HTLC-success, `cltv_expiry` for HTLC-timeout
 	 */
 	struct bitcoin_tx *tx = bitcoin_tx(ctx, chainparams, 1, 1, locktime);
-	u8 *wscript;
-	struct amount_sat amount;
 
 	/* BOLT #3:
 	 *
@@ -45,7 +42,6 @@ static struct bitcoin_tx *htlc_tx(const tal_t *ctx,
 	 *      transaction
 	 *    * `txin[0]` sequence: `0` (set to `1` for `option_anchors`)
 	 */
-	amount = amount_msat_to_sat_round_down(msat);
 	bitcoin_tx_add_input(tx, commit,
 			     option_anchor_outputs ? 1 : 0,
 			     NULL, amount, NULL, commit_wscript);
@@ -59,18 +55,14 @@ static struct bitcoin_tx *htlc_tx(const tal_t *ctx,
 	 *       below
 	 */
 	if (!amount_sat_sub(&amount, amount, htlc_fee))
-		abort();
+		return tal_free(tx);
 
-	wscript = bitcoin_wscript_htlc_tx(tx, to_self_delay, revocation_pubkey,
-					  local_delayedkey);
-	bitcoin_tx_add_output(tx, scriptpubkey_p2wsh(tmpctx, wscript),
-			      wscript, amount);
+	bitcoin_tx_add_output(tx, scriptpubkey_p2wsh(tmpctx, htlc_tx_wscript),
+			      htlc_tx_wscript, amount);
 
 	bitcoin_tx_finalize(tx);
 	assert(bitcoin_tx_check(tx));
 
-	tal_free(wscript);
-
 	return tx;
 }
 
@@ -84,14 +76,19 @@ struct bitcoin_tx *htlc_success_tx(const tal_t *ctx,
 				   const struct keyset *keyset,
 				   bool option_anchor_outputs)
 {
+	const u8 *htlc_wscript;
+
+	htlc_wscript = bitcoin_wscript_htlc_tx(tmpctx,
+					       to_self_delay,
+					       &keyset->self_revocation_key,
+					       &keyset->self_delayed_payment_key);
 	/* BOLT #3:
 	 * * locktime: `0` for HTLC-success, `cltv_expiry` for HTLC-timeout
 	 */
 	return htlc_tx(ctx, chainparams, commit,
-		       commit_wscript, htlc_msatoshi,
-		       to_self_delay,
-		       &keyset->self_revocation_key,
-		       &keyset->self_delayed_payment_key,
+		       commit_wscript,
+		       amount_msat_to_sat_round_down(htlc_msatoshi),
+		       htlc_wscript,
 		       htlc_success_fee(feerate_per_kw,
 					option_anchor_outputs),
 		       0,
@@ -137,13 +134,19 @@ struct bitcoin_tx *htlc_timeout_tx(const tal_t *ctx,
 				   const struct keyset *keyset,
 				   bool option_anchor_outputs)
 {
+	const u8 *htlc_wscript;
+
+	htlc_wscript = bitcoin_wscript_htlc_tx(tmpctx,
+					       to_self_delay,
+					       &keyset->self_revocation_key,
+					       &keyset->self_delayed_payment_key);
 	/* BOLT #3:
 	 * * locktime: `0` for HTLC-success, `cltv_expiry` for HTLC-timeout
 	 */
 	return htlc_tx(ctx, chainparams, commit,
-		       commit_wscript, htlc_msatoshi, to_self_delay,
-		       &keyset->self_revocation_key,
-		       &keyset->self_delayed_payment_key,
+		       commit_wscript,
+		       amount_msat_to_sat_round_down(htlc_msatoshi),
+		       htlc_wscript,
 		       htlc_timeout_fee(feerate_per_kw,
 					option_anchor_outputs),
 		       cltv_expiry,
diff --git a/common/htlc_tx.h b/common/htlc_tx.h
index 188b6d34d..f58608376 100644
--- a/common/htlc_tx.h
+++ b/common/htlc_tx.h
@@ -115,4 +115,14 @@ u8 *htlc_offered_wscript(const tal_t *ctx,
 			 const struct keyset *keyset,
 			 bool option_anchor_outputs);
 
+/* Low-level HTLC tx creator */
+struct bitcoin_tx *htlc_tx(const tal_t *ctx,
+			   const struct chainparams *chainparams,
+			   const struct bitcoin_outpoint *commit,
+			   const u8 *commit_wscript,
+			   struct amount_sat amount,
+			   const u8 *htlc_tx_wscript,
+			   struct amount_sat htlc_fee,
+			   u32 locktime,
+			   bool option_anchor_outputs);
 #endif /* LIGHTNING_COMMON_HTLC_TX_H */