diff --git a/src/emu/cpu/amis2000/amis2000.c b/src/emu/cpu/amis2000/amis2000.c
index d6c4967d0dc..9b227fd89b6 100644
--- a/src/emu/cpu/amis2000/amis2000.c
+++ b/src/emu/cpu/amis2000/amis2000.c
@@ -5,9 +5,9 @@
   American Microsystems, Inc.(AMI) S2000-family 4-bit MCU cores, introduced late 1970s
   
   TODO:
-  - bug(s)? - MESS wildfire.c doesn't work yet
   - unemulated opcodes (need more testing material)
   - support external program map
+  - STATUS pin(wildfire.c sound?)
   - add 50/60hz timer
   - add S2200/S2400
 
@@ -16,6 +16,8 @@
 #include "amis2000.h"
 #include "debugger.h"
 
+#include "amis2000op.inc"
+
 
 // S2000 is the most basic one, 64 nibbles internal RAM and 1KB internal ROM
 // S2150 increased RAM to 80 nibbles and ROM to 1.5KB
@@ -31,7 +33,8 @@ ADDRESS_MAP_END
 
 static ADDRESS_MAP_START(program_1_5k, AS_PROGRAM, 8, amis2000_device)
 	AM_RANGE(0x0000, 0x03ff) AM_ROM
-	AM_RANGE(0x0400, 0x05ff) AM_ROM AM_MIRROR(0x200)
+	AM_RANGE(0x0400, 0x05ff) AM_NOP
+	AM_RANGE(0x0600, 0x07ff) AM_ROM
 ADDRESS_MAP_END
 
 
@@ -151,6 +154,8 @@ void amis2000_device::device_start()
 	m_i = 0;
 	m_k = 0;
 	m_d = 0;
+	m_d_active = false;
+	m_d_polarity = 0;
 	m_a = 0;
 
 	// register for savestates
@@ -170,6 +175,8 @@ void amis2000_device::device_start()
 	save_item(NAME(m_i));
 	save_item(NAME(m_k));
 	save_item(NAME(m_d));
+	save_item(NAME(m_d_active));
+	save_item(NAME(m_d_polarity));
 	save_item(NAME(m_a));
 
 	// register state for debugger
@@ -199,10 +206,11 @@ void amis2000_device::device_reset()
 	m_op = 0;
 	
 	// clear i/o
+	m_d_polarity = 0;
+	m_d = 0; d_latch_out(false);
+	m_a = 0; m_write_a(0, 0, 0xffff);
 	m_i = 0;
 	m_k = 0;
-	m_d = 0; m_write_d(0, 0, 0xff);
-	m_a = 0; m_write_a(0, 0, 0xffff);
 }
 
 
@@ -211,8 +219,6 @@ void amis2000_device::device_reset()
 //  execute
 //-------------------------------------------------
 
-#include "amis2000op.inc"
-
 void amis2000_device::execute_run()
 {
 	while (m_icount > 0)
@@ -246,7 +252,7 @@ void amis2000_device::execute_run()
 				switch (m_op)
 				{
 			case 0x00: op_nop(); break;
-			case 0x01: op_illegal(); break; // reserved for devkit-use
+			case 0x01: op_halt(); break;
 			case 0x02: op_rt(); break;
 			case 0x03: op_rts(); break;
 			case 0x04: op_psh(); break;
diff --git a/src/emu/cpu/amis2000/amis2000.h b/src/emu/cpu/amis2000/amis2000.h
index d8960bfd062..18c3b5d43a3 100644
--- a/src/emu/cpu/amis2000/amis2000.h
+++ b/src/emu/cpu/amis2000/amis2000.h
@@ -92,6 +92,8 @@ protected:
 	UINT8 m_i;                  // 4-bit i-pins latch
 	UINT8 m_k;                  // 4-bit k-pins latch
 	UINT8 m_d;                  // 8-bit d-pins latch
+	bool m_d_active;            // d-pins available for direct i/o(floating), or outputting d-latch
+	UINT8 m_d_polarity;         // invert d-latch output
 	UINT16 m_a;                 // 13-bit a-pins latch (master strobe latch)
 
 	devcb_read8 m_read_k;
@@ -106,7 +108,7 @@ protected:
 	void ram_w(UINT8 data);
 	void pop_callstack();
 	void push_callstack();
-	void op_illegal();
+	void d_latch_out(bool active);
 	
 	void op_lai();
 	void op_lab();
@@ -141,6 +143,7 @@ protected:
 	void op_rt();
 	void op_rts();
 	void op_nop();
+	void op_halt();
 
 	void op_szc();
 	void op_szm();
diff --git a/src/emu/cpu/amis2000/amis2000d.c b/src/emu/cpu/amis2000/amis2000d.c
index 81fc59b58d9..0c9079a3b3e 100644
--- a/src/emu/cpu/amis2000/amis2000d.c
+++ b/src/emu/cpu/amis2000/amis2000d.c
@@ -17,9 +17,8 @@ enum e_mnemonics
 	mLAM, mXC, mXCI, mXCD, mSTM, mRSM,
 	mADD, mADCS, mADIS, mAND, mXOR, mCMA, mSTC, mRSC, mSF1, mRF1, mSF2, mRF2,
 	mSAM, mSZM, mSBE, mSZC, mSOS, mSZK, mSZI, mTF1, mTF2,
-	mPP, mJMP, mJMS, mRT, mRTS, mNOP,
-	mINP, mOUT, mDISB, mDISN, mMVS, mPSH, mPSL, mEUR,
-	mILL
+	mPP, mJMP, mJMS, mRT, mRTS, mNOP, mHALT,
+	mINP, mOUT, mDISB, mDISN, mMVS, mPSH, mPSL, mEUR
 };
 
 static const char *const s_mnemonics[] =
@@ -28,9 +27,8 @@ static const char *const s_mnemonics[] =
 	"LAM", "XC", "XCI", "XCD", "STM", "RSM",
 	"ADD", "ADCS", "ADIS", "AND", "XOR", "CMA", "STC", "RSC", "SF1", "RF1", "SF2", "RF2",
 	"SAM", "SZM", "SBE", "SZC", "SOS", "SZK", "SZI", "TF1", "TF2",
-	"PP", "JMP", "JMS", "RT", "RTS", "NOP",
-	"INP", "OUT", "DISB", "DISN", "MVS", "PSH", "PSL", "EUR",
-	"?"
+	"PP", "JMP", "JMS", "RT", "RTS", "NOP", "HALT",
+	"INP", "OUT", "DISB", "DISN", "MVS", "PSH", "PSL", "EUR"
 };
 
 
@@ -43,9 +41,8 @@ static const UINT32 s_flags[] =
 	0, 0, 0, 0, 0, 0,
 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 	0, 0, 0, 0, 0, 0, 0, 0, 0,
-	0, 0, _OVER, _OUT, _OUT, 0,
-	0, 0, 0, 0, 0, 0, 0, 0,
-	0
+	0, 0, _OVER, _OUT, _OUT, 0, 0,
+	0, 0, 0, 0, 0, 0, 0, 0
 };
 
 
@@ -55,16 +52,15 @@ static const int s_bits[] =
 	-2, -2, -2, -2, 2, 2,
 	0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 	0, 2, 0, 0, 0, 0, 0, 0, 0,
-	-4, 6, 6, 0, 0, 0,
+	-4, 6, 6, 0, 0, 0, 0,
 	0, 0, 0, 0, 0, 0, 0, 0,
-	0
 };
 
 
 static const UINT8 s2000_mnemonic[0x100] =
 {
 	/* 0x00 */
-	mNOP, mILL, mRT, mRTS, mPSH, mPSL, mAND, mSOS,
+	mNOP, mHALT, mRT, mRTS, mPSH, mPSL, mAND, mSOS,
 	mSBE, mSZC, mSTC, mRSC, mLAE, mXAE, mINP, mEUR,
 	/* 0x10 */
 	mCMA, mXABU, mLAB, mXAB, mADCS, mXOR, mADD, mSAM,
diff --git a/src/emu/cpu/amis2000/amis2000op.inc b/src/emu/cpu/amis2000/amis2000op.inc
index 504fc174379..ed6f6158d89 100644
--- a/src/emu/cpu/amis2000/amis2000op.inc
+++ b/src/emu/cpu/amis2000/amis2000op.inc
@@ -33,9 +33,10 @@ void amis2000_device::push_callstack()
 	m_callstack[0] = m_pc & m_callstack_mask;
 }
 
-void amis2000_device::op_illegal()
+void amis2000_device::d_latch_out(bool active)
 {
-	logerror("%s unknown opcode $%02X at $%04X\n", tag(), m_op, m_pc);
+	m_write_d(0, active ? (m_d ^ m_d_polarity) : 0, 0xff);
+	m_d_active = active;
 }
 
 
@@ -195,21 +196,22 @@ void amis2000_device::op_rsm()
 void amis2000_device::op_inp()
 {
 	// INP: input D-pins to ACC and RAM
-	op_illegal();
+	UINT8 in = m_d_active ? m_d : m_read_d(0, 0xff);
+	m_acc = in & 0xf;
+	ram_w(in >> 4 & 0xf);
 }
 
 void amis2000_device::op_out()
 {
 	// OUT: pulse output ACC and RAM to D-pins
-	op_illegal();
+	logerror("%s unknown opcode $%02X at $%04X\n", tag(), m_op, m_pc);
 }
 
 void amis2000_device::op_disb()
 {
 	// DISB: set D-latch to ACC and RAM directly
 	m_d = m_acc | ram_r() << 4;
-	m_write_d(0, m_d, 0xff);
-	// TODO: exit from floating mode on D-pins
+	d_latch_out(true);
 }
 
 void amis2000_device::op_disn()
@@ -221,15 +223,14 @@ void amis2000_device::op_disn()
 		0x7e, 0x30, 0x6d, 0x79, 0x33, 0x5b, 0x5f, 0x70, 0x7f, 0x7b, 0x77, 0x1f, 0x4e, 0x3d, 0x4f, 0x47
 	};
 	m_d = lut_segment_decoder[m_acc] | (m_carry ? 0x80 : 0x00);
-	m_write_d(0, m_d, 0xff);
-	// TODO: exit from floating mode on D-pins
+	d_latch_out(true);
 }
 
 void amis2000_device::op_mvs()
 {
 	// MVS: output master strobe latch to A-pins
+	d_latch_out(false);
 	m_write_a(0, m_a, 0xffff);
-	// TODO: enter floating mode on D-pins
 }
 
 void amis2000_device::op_psh()
@@ -244,7 +245,7 @@ void amis2000_device::op_psh()
 
 		case 0xe:
 			// exit from floating mode on D-pins
-			// ?
+			d_latch_out(true);
 			break;
 
 		case 0xf:
@@ -271,7 +272,7 @@ void amis2000_device::op_psl()
 
 		case 0xe:
 			// enter floating mode on D-pins
-			// ?
+			d_latch_out(false);
 			break;
 
 		case 0xf:
@@ -288,8 +289,9 @@ void amis2000_device::op_psl()
 
 void amis2000_device::op_eur()
 {
-	// EUR: set timer frequency(European) and D-latch polarity
-	op_illegal();
+	// EUR: set timer frequency(European) and D-latch polarity, via ACC
+	m_d_polarity = (m_acc & 1) ? 0x00 : 0xff;
+	d_latch_out(m_d_active); // refresh
 }
 
 
@@ -350,6 +352,12 @@ void amis2000_device::op_nop()
 	// NOP: no operation
 }
 
+void amis2000_device::op_halt()
+{
+	// HALT: debugger breakpoint for devkit-use
+	logerror("%s unknown opcode $%02X at $%04X\n", tag(), m_op, m_pc);
+}
+
 
 // Skip Instructions
 
@@ -393,7 +401,7 @@ void amis2000_device::op_sam()
 void amis2000_device::op_sos()
 {
 	// SOS: skip next on SF(timer output), clear SF
-	op_illegal();
+	logerror("%s unknown opcode $%02X at $%04X\n", tag(), m_op, m_pc);
 }
 
 void amis2000_device::op_tf1()
diff --git a/src/mess/drivers/wildfire.c b/src/mess/drivers/wildfire.c
index 39db9be728f..f147aee90c2 100644
--- a/src/mess/drivers/wildfire.c
+++ b/src/mess/drivers/wildfire.c
@@ -108,8 +108,9 @@ MACHINE_CONFIG_END
 ***************************************************************************/
 
 ROM_START( wildfire )
-	ROM_REGION( 0x0600, "maincpu", 0 )
-	ROM_LOAD( "us4341385", 0x0000, 0x0600, CRC(84ac0f1f) SHA1(1e00ddd402acfc2cc267c34eed4b89d863e2144f) ) // from patent US4334679, data should be correct (it included checksums)
+	ROM_REGION( 0x0800, "maincpu", ROMREGION_ERASE00 )
+	ROM_LOAD( "us4341385", 0x0000, 0x0400, CRC(84ac0f1f) SHA1(1e00ddd402acfc2cc267c34eed4b89d863e2144f) ) // from patent US4334679, data should be correct (it included checksums)
+	ROM_CONTINUE(          0x0600, 0x0200 )
 ROM_END