diff --git a/src/mame/audio/cmi01a.cpp b/src/mame/audio/cmi01a.cpp
index cd5764356d4..5577805856f 100644
--- a/src/mame/audio/cmi01a.cpp
+++ b/src/mame/audio/cmi01a.cpp
@@ -252,7 +252,7 @@ void cmi01a_device::pulse_gzx()
 void cmi01a_device::reset_waveform_segment()
 {
 	m_segment_cnt &= 0x007f;
-	m_segment_cnt = 0x4000 | (m_ws << 7);
+	m_segment_cnt |= (0x4000 | (m_ws << 7));
 }
 
 void cmi01a_device::load_w(int state)
diff --git a/src/mame/video/fm7.cpp b/src/mame/video/fm7.cpp
index e8848220c10..69567c85688 100644
--- a/src/mame/video/fm7.cpp
+++ b/src/mame/video/fm7.cpp
@@ -363,10 +363,13 @@ void fm77_state::alu_function_not(uint32_t offset)
 	{
 		if(!(m_alu.bank_disable & (1 << x)))
 		{
+#ifdef UNUSED
+			// "dat" is overwritten before it can get used: Coverity 315775
 			if(m_alu.lcolour & (1 << x))
 				dat = 0xff;
 			else
 				dat = 0;
+#endif
 
 			mask = (m_video_ram[(offset & 0x3fff) + (x * 0x4000) + (page * 0xc000)]);
 			dat = ~mask;