diff --git a/software/sys_controller/it6613/it6613_drv.c b/software/sys_controller/it6613/it6613_drv.c
index 42fde5e..cf5aced 100644
--- a/software/sys_controller/it6613/it6613_drv.c
+++ b/software/sys_controller/it6613/it6613_drv.c
@@ -3401,6 +3401,8 @@ SetGPInfoFrame(BYTE *pInfoFrameData)
         return ER_FAIL ;
     }
 
+    DISABLE_NULL_PKT();
+
     Switch_HDMITX_Bank(1) ;
 
     HDMITX_WriteI2C_Byte(REG_TX_PKT_HB00, (0x80+pInfoFrame->info.Type));
diff --git a/software/sys_controller/ossc/av_controller.c b/software/sys_controller/ossc/av_controller.c
index d4d7d81..591b54c 100644
--- a/software/sys_controller/ossc/av_controller.c
+++ b/software/sys_controller/ossc/av_controller.c
@@ -185,6 +185,7 @@ inline void TX_enable(tx_mode_t mode)
     SetAVMute(TRUE);
     DisableVideoOutput();
     EnableAVIInfoFrame(FALSE, NULL);
+    EnableGPInfoFrame(FALSE, NULL);
 
     //Setup TX configuration
     //TODO: set pclk target and VIC dynamically
@@ -192,8 +193,10 @@ inline void TX_enable(tx_mode_t mode)
 
     if (mode != TX_DVI) {
         HDMITX_SetAVIInfoFrame(vmode_out.vic, (mode == TX_HDMI_RGB) ? F_MODE_RGB444 : F_MODE_YUV444, 0, 0, tc.hdmi_itc, vm_conf.hdmitx_pixr_ifr);
-        HDMITX_SetHDRInfoFrame(tc.hdmi_hdr ? 3 : 0);
-        HDMITX_SetVRRInfoFrame(tc.hdmi_vrr);
+        if (tc.hdmi_vrr)
+            HDMITX_SetVRRInfoFrame(tc.hdmi_vrr);
+        if (tc.hdmi_hdr)
+            HDMITX_SetHDRInfoFrame(tc.hdmi_hdr ? 3 : 0);
         cm.cc.hdmi_itc = tc.hdmi_itc;
         cm.cc.hdmi_hdr = tc.hdmi_hdr;
         cm.cc.hdmi_vrr = tc.hdmi_vrr;
@@ -1162,16 +1165,16 @@ int main()
                 HDMITX_SetAVIInfoFrame(vmode_out.vic, (tc.tx_mode == TX_HDMI_RGB) ? F_MODE_RGB444 : F_MODE_YUV444, 0, 0, tc.hdmi_itc, vm_conf.hdmitx_pixr_ifr);
                 cm.cc.hdmi_itc = tc.hdmi_itc;
             }
-            if (tc.hdmi_hdr != cm.cc.hdmi_hdr) {
-                printf("setting HDR flag to %d\n", tc.hdmi_hdr);
-                HDMITX_SetHDRInfoFrame(tc.hdmi_hdr ? 3 : 0);
-                cm.cc.hdmi_hdr = tc.hdmi_hdr;
-            }
             if (tc.hdmi_vrr != cm.cc.hdmi_vrr) {
                 printf("setting VRR flag to %d\n", tc.hdmi_vrr);
                 HDMITX_SetVRRInfoFrame(tc.hdmi_vrr);
                 cm.cc.hdmi_vrr = tc.hdmi_vrr;
             }
+            if (tc.hdmi_hdr != cm.cc.hdmi_hdr) {
+                printf("setting HDR flag to %d\n", tc.hdmi_hdr);
+                HDMITX_SetHDRInfoFrame(tc.hdmi_hdr ? 3 : 0);
+                cm.cc.hdmi_hdr = tc.hdmi_hdr;
+            }
         }
         if (tc.av3_alt_rgb != cm.cc.av3_alt_rgb) {
             printf("Changing AV3 RGB source\n");