diff --git a/Components/DiskII/IWM.cpp b/Components/DiskII/IWM.cpp
index 6e2a0553c..2c6af7ee6 100644
--- a/Components/DiskII/IWM.cpp
+++ b/Components/DiskII/IWM.cpp
@@ -102,7 +102,7 @@ uint8_t IWM::read(int address) {
 
 				case SEL:				// Disk in place.
 					LOG("disk in place)");
-					sense = drives_[active_drive_] && drives_[active_drive_]->has_disk() ? 0x00 : 0x80;
+					sense = drives_[active_drive_] && drives_[active_drive_]->has_disk() ? 0 : 1;
 				break;
 
 //				case CA0:				// Disk head step completed (1 = still stepping?).
@@ -112,21 +112,21 @@ uint8_t IWM::read(int address) {
 				case CA0|SEL:			// Disk locked (i.e. write-protect tab).
 					LOG("disk locked)");
 //					sense = drives_[active_drive_] && drives_[active_drive_]->get_is_read_only() ? 0x00 : 0x80;
-					sense = drives_[active_drive_] && drives_[active_drive_]->get_is_read_only() ? 0x80 : 0x00;
+					sense = drives_[active_drive_] && drives_[active_drive_]->get_is_read_only() ? 1 : 0;
 				break;
 
 				case CA1:				// Disk motor running.
 					LOG("disk motor running)");
-					sense = drives_[active_drive_] && drives_[active_drive_]->get_motor_on() ? 0x00 : 0x80;
+					sense = drives_[active_drive_] && drives_[active_drive_]->get_motor_on() ? 0 : 1;
 				break;
 
 				case CA1|SEL:			// Head at track 0.
 					LOG("head at track 0)");
-					sense = drives_[active_drive_] && drives_[active_drive_]->get_is_track_zero() ? 0x00 : 0x80;
+					sense = drives_[active_drive_] && drives_[active_drive_]->get_is_track_zero() ? 0 : 1;
 				break;
 
 				case CA1|CA0|SEL:		// Tachometer (?)
-					sense = drives_[active_drive_] && drives_[active_drive_]->get_tachometer() ? 0x00 : 0x80;
+					sense = drives_[active_drive_] && drives_[active_drive_]->get_tachometer() ? 0 : 1;
 					LOG("tachometer " << PADHEX(2) << int(sense) << ")");
 				break;
 
@@ -140,20 +140,25 @@ uint8_t IWM::read(int address) {
 //
 				case CA2|CA1:			// Single- or double-sided drive.
 					LOG("single- or double-sided drive)");
-					sense = drives_[active_drive_] && (drives_[active_drive_]->get_head_count() == 1) ? 0x80 : 0x00;
+					sense = drives_[active_drive_] && (drives_[active_drive_]->get_head_count() == 1) ? 1 : 0;
+				break;
+
+				case CA2|CA1|CA0:		// Present/HD.			(per the Mac Plus ROM)
+					LOG("present/HD)");
+					sense = drives_[active_drive_] ? 0 : 1;
 				break;
 
-				case CA2|CA1|CA0:		// Drive installed.		(per the Mac Plus ROM)
 				case CA2|CA1|CA0|SEL:	// Drive installed.		(per Inside Macintosh)
 					LOG("drive installed)");
-					sense = drives_[active_drive_] ? 0x00 : 0x80;
+					sense = drives_[active_drive_] ? 0 : 1;
 				break;
 			}
 
-			return
+			return uint8_t(
 				(mode_&0x1f) |
 				(drive_motor_on_ ? 0x20 : 0x00) |
-				sense;
+				(sense << 7)
+			);
 		} break;
 
 		case Q7: case Q7|ENABLE:
diff --git a/Machines/Apple/Macintosh/Macintosh.cpp b/Machines/Apple/Macintosh/Macintosh.cpp
index bceb72964..c16a569d7 100644
--- a/Machines/Apple/Macintosh/Macintosh.cpp
+++ b/Machines/Apple/Macintosh/Macintosh.cpp
@@ -217,7 +217,7 @@ template <Analyser::Static::Macintosh::Target::Model model> class ConcreteMachin
 
 							case 0x68f000:
 								// The IWM; this is a purely polled device, so can be run on demand.
-//								printf("[%06x]: ", mc68000_.get_state().program_counter);
+								printf("[%06x]: ", mc68000_.get_state().program_counter);
 								iwm_.flush();
 								if(cycle.operation & Microcycle::Read) {
 									cycle.value->halves.low = iwm_.iwm.read(register_address);
@@ -295,6 +295,10 @@ template <Analyser::Static::Macintosh::Target::Model model> class ConcreteMachin
 							if(!(operation & Microcycle::Read) || word_address >= 0x300000) operation = 0;
 						}
 
+						if(!(operation & Microcycle::Read) && (word_address == (0x0000182e >> 1))) {
+							printf("Write to 0000182e: %04x from %08x\n", cycle.value->full, mc68000_.get_state().program_counter);
+						}
+
 						const auto masked_operation = operation & (Microcycle::SelectWord | Microcycle::SelectByte | Microcycle::Read | Microcycle::InterruptAcknowledge);
 						switch(masked_operation) {
 							default:
diff --git a/OSBindings/Mac/Clock Signal.xcodeproj/xcshareddata/xcschemes/Clock Signal.xcscheme b/OSBindings/Mac/Clock Signal.xcodeproj/xcshareddata/xcschemes/Clock Signal.xcscheme
index cdac581d4..9c2dca9ce 100644
--- a/OSBindings/Mac/Clock Signal.xcodeproj/xcshareddata/xcschemes/Clock Signal.xcscheme	
+++ b/OSBindings/Mac/Clock Signal.xcodeproj/xcshareddata/xcschemes/Clock Signal.xcscheme	
@@ -69,7 +69,7 @@
       </AdditionalOptions>
    </TestAction>
    <LaunchAction
-      buildConfiguration = "Release"
+      buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       enableASanStackUseAfterReturn = "YES"
diff --git a/Processors/68000/Implementation/68000Implementation.hpp b/Processors/68000/Implementation/68000Implementation.hpp
index b871b1122..068ff131c 100644
--- a/Processors/68000/Implementation/68000Implementation.hpp
+++ b/Processors/68000/Implementation/68000Implementation.hpp
@@ -291,8 +291,9 @@ template <class T, bool dtack_is_implicit, bool signal_will_perform> void Proces
 #ifdef LOG_TRACE
 							const uint32_t fetched_pc = (program_counter_.full - 4)&0xffffff;
 
+							should_log |= fetched_pc >= 0x417E66;
 //1300
-							should_log = (fetched_pc >= 0x400D9A) && (fetched_pc <= 0x400EAA);
+//							should_log = (fetched_pc >= 0x400D9A) && (fetched_pc <= 0x400EAA);
 							// == 0x0003ea);
 //							should_log |=
 //								(((program_counter_.full - 4)&0xffffff) == 0x418CDE) ||	// E_Sony_RdData