diff --git a/LOG b/LOG
index 512c8c4ea..2c8712d0b 100644
--- a/LOG
+++ b/LOG
@@ -2373,3 +2373,5 @@
 - fix repair to invalid live-pointer mask, where a pass did not handle the
   new raw-data form correctly
     mats/fx.ms s/cpnanopass.ss
+- avoid sime trivial warnings related to abnormal exit and fallthrough.
+    c/scheme.c c/schsig.c
diff --git a/c/scheme.c b/c/scheme.c
index 2f20082b6..23ea009c5 100644
--- a/c/scheme.c
+++ b/c/scheme.c
@@ -989,7 +989,7 @@ extern void Sscheme_init(void (*abnormal_exit)(void)) {
     case BOOTING:
       fprintf(stderr, "error (Sscheme_init): already initialized\n");
       S_abnormal_exit();
-      break;
+      break;	/* Pacify compilers treating fallthrough warnings as errors */
     case UNINITIALIZED:
     case DEINITIALIZED:
       break;
@@ -1075,7 +1075,7 @@ extern void Sbuild_heap(const char *kernel, void (*custom_init)(void)) {
     case RUNNING:
       fprintf(stderr, "error (Sbuild_heap): already running\n");
       S_abnormal_exit();
-      break;
+      break;	/* Pacify compilers treating fallthrough warnings as errors */
     case BOOTING:
       break;
   }
@@ -1183,7 +1183,7 @@ extern INT Sscheme_start(INT argc, const char *argv[]) {
     case BOOTING:
       fprintf(stderr, "error (Sscheme_start): no heap built yet; call Sbuild_heap first\n");
       S_abnormal_exit();
-      break;
+      break;	/* Pacify compilers treating fallthrough warnings as errors */
     case RUNNING:
       break;
   }
@@ -1219,7 +1219,7 @@ static INT run_script(const char *who, const char *scriptfile, INT argc, const c
     case BOOTING:
       fprintf(stderr, "error (%s): no heap built yet; call Sbuild_heap first\n", who);
       S_abnormal_exit();
-      break;
+      break;	/* Pacify compilers treating fallthrough warnings as errors */
     case RUNNING:
       break;
   }
@@ -1269,7 +1269,7 @@ extern void Sscheme_deinit(void) {
     case BOOTING:
       fprintf(stderr, "error (Sscheme_deinit): not yet running\n");
       S_abnormal_exit();
-      break;
+      break;	/* Pacify compilers treating fallthrough warnings as errors */
     case RUNNING:
       break;
   }
diff --git a/c/schsig.c b/c/schsig.c
index 227b61494..c2b3cba92 100644
--- a/c/schsig.c
+++ b/c/schsig.c
@@ -673,11 +673,11 @@ static void handle_signal(INT sig, UNUSED siginfo_t *si, UNUSED void *data) {
         case SIGILL:
             RESET_SIGNAL
             S_error_reset("illegal instruction");
-	    break;
+	    break;	/* Pacify compilers treating fallthrough warnings as errors */
         case SIGFPE:
             RESET_SIGNAL
             S_error_reset("arithmetic overflow");
-	    break;
+	    break;	/* Pacify compilers treating fallthrough warnings as errors */
 #ifdef SIGBUS
         case SIGBUS:
 #endif /* SIGBUS */