diff --git a/core/bitops.h b/core/bitops.h
index 786441d..72f0384 100644
--- a/core/bitops.h
+++ b/core/bitops.h
@@ -26,7 +26,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 #include <cinttypes>
 
-#if defined(__GNUG__) && !defined(__clang__) // GCC, mybe ICC but not Clang
+#if defined(__GNUG__) && !defined(__clang__)  && (defined(__x86_64__) || defined(__i386__)) // GCC, mybe ICC but not Clang
 
 #   include <x86intrin.h>
 
diff --git a/devices/common/scsi/scsibus.cpp b/devices/common/scsi/scsibus.cpp
index 01b4144..2f6cfff 100644
--- a/devices/common/scsi/scsibus.cpp
+++ b/devices/common/scsi/scsibus.cpp
@@ -67,6 +67,8 @@ void ScsiBus::change_bus_phase(int initiator_id)
 
 void ScsiBus::assert_ctrl_line(int initiator_id, uint16_t mask)
 {
+    DCHECK_F(initiator_id >= 0 && initiator_id < SCSI_MAX_DEVS, "ScsiBus: invalid initiator ID %d", initiator_id);
+
     uint16_t new_state = 0xFFFFU & mask;
 
     this->dev_ctrl_lines[initiator_id] |= new_state;
@@ -84,6 +86,8 @@ void ScsiBus::assert_ctrl_line(int initiator_id, uint16_t mask)
 
 void ScsiBus::release_ctrl_line(int id, uint16_t mask)
 {
+    DCHECK_F(id >= 0 && id < SCSI_MAX_DEVS, "ScsiBus: invalid initiator ID %d", id);
+
     uint16_t new_state = 0;
 
     this->dev_ctrl_lines[id] &= ~mask;
diff --git a/main.cpp b/main.cpp
index 5b9a18a..b85ea22 100644
--- a/main.cpp
+++ b/main.cpp
@@ -140,7 +140,7 @@ int main(int argc, char** argv) {
         machine_str = MachineFactory::machine_name_from_rom(bootrom_path);
         if (machine_str.empty()) {
             LOG_F(ERROR, "Could not autodetect machine");
-            return 0;
+            return 1;
         }
         else {
             LOG_F(INFO, "Machine was autodetected as: %s", machine_str.c_str());
@@ -150,7 +150,7 @@ int main(int argc, char** argv) {
     /* handle overriding of machine settings from command line */
     map<string, string> settings;
     if (MachineFactory::get_machine_settings(machine_str, settings) < 0) {
-        return 0;
+        return 1;
     }
 
     CLI::App sa;
@@ -168,7 +168,7 @@ int main(int argc, char** argv) {
 
     if (SDL_Init(SDL_INIT_VIDEO)) {
         LOG_F(ERROR, "SDL_Init error: %s", SDL_GetError());
-        return 0;
+        return 1;
     }
 
     // initialize global profiler object
@@ -180,6 +180,9 @@ int main(int argc, char** argv) {
 
     // graceful handling of fatal errors
     loguru::set_fatal_handler([](const loguru::Message& message) {
+        // Make sure the reason for the failure is visible (it may have been
+        // sent to the logfile only).
+        cerr << message.preamble << message.indentation << message.prefix << message.message << endl;
         enter_debugger();
 
         abort();
@@ -206,7 +209,7 @@ int main(int argc, char** argv) {
         break;
     default:
         LOG_F(ERROR, "Invalid EXECUTION MODE");
-        return 0;
+        return 1;
     }
 
 bail: