diff --git a/src/devices/machine/pic8259.cpp b/src/devices/machine/pic8259.cpp
index 40fe6fd916c..3064e212850 100644
--- a/src/devices/machine/pic8259.cpp
+++ b/src/devices/machine/pic8259.cpp
@@ -133,7 +133,10 @@ UINT32 pic8259_device::acknowledge()
 			}
 		}
 	}
-	return 0;
+	logerror("Spurious IRQ\n");
+	if(m_is_x86)
+		return m_base + 7;
+	return 0xcd0000 + (m_vector_addr_high << 8) + m_vector_addr_low + (7 << (3-m_vector_size));
 }
 
 
diff --git a/src/mame/drivers/pc9801.cpp b/src/mame/drivers/pc9801.cpp
index 66670fe7c9a..7185014c285 100644
--- a/src/mame/drivers/pc9801.cpp
+++ b/src/mame/drivers/pc9801.cpp
@@ -734,6 +734,7 @@ public:
 		UINT8 freq_index;
 	}m_mouse;
 	TIMER_DEVICE_CALLBACK_MEMBER( mouse_irq_cb );
+	DECLARE_READ8_MEMBER(unk_r);
 
 	DECLARE_DRIVER_INIT(pc9801_kanji);
 	inline void set_dma_channel(int channel, int state);
@@ -2485,6 +2486,7 @@ static ADDRESS_MAP_START( pc9821_io, AS_IO, 32, pc9801_state )
 	AM_RANGE(0x0050, 0x0053) AM_WRITE8(pc9801rs_nmi_w, 0xffffffff)
 	AM_RANGE(0x005c, 0x005f) AM_READ16(pc9821_timestamp_r,0xffffffff) AM_WRITENOP // artic
 	AM_RANGE(0x0060, 0x0063) AM_DEVREADWRITE8("upd7220_chr", upd7220_device, read, write, 0x00ff00ff) //upd7220 character ports / <undefined>
+	AM_RANGE(0x0060, 0x0063) AM_READ8(unk_r, 0xff00ff00) // mouse related (unmapped checking for AT keyb controller\PS/2 mouse?)
 	AM_RANGE(0x0064, 0x0067) AM_WRITE8(vrtc_clear_w, 0x000000ff)
 	AM_RANGE(0x0068, 0x006b) AM_WRITE8(pc9821_video_ff_w,  0x00ff00ff) //mode FF / <undefined>
 	AM_RANGE(0x0070, 0x007f) AM_DEVREADWRITE8("pit8253", pit8253_device, read, write, 0xff00ff00)
@@ -2969,6 +2971,11 @@ WRITE8_MEMBER(pc9801_state::ppi_mouse_portc_w)
 	m_mouse.control = data;
 }
 
+READ8_MEMBER(pc9801_state::unk_r)
+{
+	return 0xff;
+}
+
 /****************************************
 *
 * UPD765 interface
diff --git a/src/mame/video/x68k.cpp b/src/mame/video/x68k.cpp
index 13f6288b642..7a11c89175b 100644
--- a/src/mame/video/x68k.cpp
+++ b/src/mame/video/x68k.cpp
@@ -867,7 +867,7 @@ bool x68k_state::x68k_draw_gfx_scanline( bitmap_ind16 &bitmap, rectangle cliprec
 									else
 										bitmap.pix16(scanline, pixel) = (pal[colour] & 0xfffe) + blend;
 								}
-								if(((m_video.reg[2] & 0x1800) == 0x1000) && (colour & 1))
+								else if(((m_video.reg[2] & 0x1800) == 0x1000) && (colour & 1))
 									m_special.pix16(scanline, pixel) = colour;
 								else
 									bitmap.pix16(scanline, pixel) = colour;