From 9f376fbca88db3e9fd169a8b145b7d6932a020a9 Mon Sep 17 00:00:00 2001
From: Floogle <18466542+skyfloogle@users.noreply.github.com>
Date: Sun, 1 Mar 2026 09:40:02 +0100
Subject: [PATCH] VSU: fix modmask triggering for every channel

---
 emu/cores/vsu.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/emu/cores/vsu.c b/emu/cores/vsu.c
index e56c8e83..b85c4739 100644
--- a/emu/cores/vsu.c
+++ b/emu/cores/vsu.c
@@ -304,7 +304,10 @@ static void VSU_Write(void* info, UINT16 A, UINT8 V)
 				chip->Frequency[ch] |= V << 0;
 				chip->EffFreq[ch] &= 0xFF00;
 				chip->EffFreq[ch] |= V << 0;
-				chip->ModLock = 1;
+				if (ch == 4)
+				{
+					chip->ModLock = 1;
+				}
 				break;
 
 			case 0x3:
@@ -312,7 +315,10 @@ static void VSU_Write(void* info, UINT16 A, UINT8 V)
 				chip->Frequency[ch] |= (V & 0x7) << 8;
 				chip->EffFreq[ch] &= 0x00FF;
 				chip->EffFreq[ch] |= (V & 0x7) << 8;
-				chip->ModLock = 2;
+				if (ch == 4)
+				{
+					chip->ModLock = 2;
+				}
 				break;
 
 			case 0x4: