diff --git a/src/mess/drivers/apple3.c b/src/mess/drivers/apple3.c
index acc3ab1dff0..a66c2d7084b 100644
--- a/src/mess/drivers/apple3.c
+++ b/src/mess/drivers/apple3.c
@@ -293,4 +293,4 @@ ROM_START(apple3)
 ROM_END
 
 /*     YEAR     NAME        PARENT  COMPAT  MACHINE    INPUT    INIT    COMPANY             FULLNAME */
-COMP( 1980, apple3,     0,      0,      apple3,    apple3, apple3_state,    apple3,     "Apple Computer",   "Apple ///", GAME_NOT_WORKING )
+COMP( 1980, apple3,     0,      0,      apple3,    apple3, apple3_state,    apple3,     "Apple Computer",   "Apple ///", 0 )
diff --git a/src/mess/includes/apple3.h b/src/mess/includes/apple3.h
index 3a6cdde7b5a..ed4c54c403e 100644
--- a/src/mess/includes/apple3.h
+++ b/src/mess/includes/apple3.h
@@ -112,6 +112,7 @@ public:
 	DECLARE_WRITE_LINE_MEMBER(ay3600_data_ready_w);
 
 	bool m_sync;
+	bool m_rom_has_been_disabled;
 	UINT8 m_indir_opcode;
 	int m_indir_count;
 
diff --git a/src/mess/machine/apple3.c b/src/mess/machine/apple3.c
index 154875cd6be..edccce47e15 100644
--- a/src/mess/machine/apple3.c
+++ b/src/mess/machine/apple3.c
@@ -346,9 +346,17 @@ void apple3_state::apple3_update_memory()
 
 	/* install bank 7 (F000-FFFF) */
 	if (m_via_0_a & 0x01)
+	{
 		m_bank7 = memregion("maincpu")->base();
+	}
 	else
+	{
+		m_rom_has_been_disabled = true;
 		m_bank7 = apple3_bankaddr(~0, 0x7000);
+
+		// if we had an IRQ waiting for RAM to be paged in...
+		apple3_irq_update();
+	}
 }
 
 
@@ -388,7 +396,18 @@ void apple3_state::apple3_irq_update()
 {
 	if (m_via_1_irq || m_via_0_irq)
 	{
-//		printf("   asserting IRQ\n");
+		// HACK: SOS floppy driver enables ROM at Fxxx *before* trying to
+		// suppress IRQs.  IRQ hits at inopportune time -> bad vector -> system crash.
+		// This breaks the Confidence Test, but the Confidence Test
+		// never disables the ROM so checking for that gets us 
+		// working in all cases.
+		// Bonus points: for some reason this isn't a problem with -debug.
+		// m6502 heisenbug maybe?
+		if ((m_via_0_a & 0x01) && (m_rom_has_been_disabled))
+		{
+			return;
+		}
+//		printf("   setting IRQ\n");
 		m_maincpu->set_input_line(M6502_IRQ_LINE, ASSERT_LINE);
 		m_via_1->write_pa7(0);	// this is active low
 	}
@@ -424,6 +443,7 @@ MACHINE_RESET_MEMBER(apple3_state,apple3)
 	m_c040_time = 0;
 	m_strobe = 0;
 	m_lastchar = 0x0d;
+	m_rom_has_been_disabled = false;
 }