diff --git a/scheme48vm.c b/scheme48vm.c
index 5332b97..8dfac72 100644
--- a/scheme48vm.c
+++ b/scheme48vm.c
@@ -3480,7 +3480,14 @@ long Tinterpret()
   RSstackS = SstackS;
   RScode_pointerS = Scode_pointerS;
   RSenvS = SenvS;
-  post_gc_fdports(); /* Hack for scsh's i/o system. Olin. */
+  /* Do NOT put a call to the scsh I/O gc hook post_gc_fdports() here.
+  ** This GC is not for real -- it's for writing images, and will be
+  ** aborted. But the part of post_gc_fdports that updates the fdports[]
+  ** elements to point into new-space *won't* be aborted, and oops, we're
+  ** pointing into hyperspace. This whole thing is a mess; we need to port
+  ** to a newer Scheme 48 release that gives us structured GC hooks.
+  **     -Olin
+  */
   close_untraced_portsB_return_tag = 0;
   goto close_untraced_portsB;
  close_untraced_portsB_return_0:
diff --git a/scsh/fdports1.c b/scsh/fdports1.c
index 3a44cd5..95e4a28 100644
--- a/scsh/fdports1.c
+++ b/scsh/fdports1.c
@@ -301,17 +301,16 @@ void post_gc_fdports(void)
 {
     int fd;
 
-#if 0
+#ifdef NOISY_FDGC
     fputs("{GC", stderr); fflush(stderr);
 #endif
     for(fd=0; fd<NUM_FDPORTS; fd++) {
 
 	scheme_value port = fdports[fd];
-
 	if(STOBP(port)) {
 	    long header = STOB_HEADER(port);
 	    if(STOBP(header)) {
-#if 0
+#ifdef NOISY_FDGC
 		fprintf(stderr, "Copying port[fd] %d[%d] header %d\n",
 			port, fd, header);
 		fflush(stderr);
@@ -324,7 +323,7 @@ void post_gc_fdports(void)
 		/* Port wasn't copied -- is garbage.
 		   If fd unrevealed, close it. */
 		int rev = EXTRACT_FIXNUM(*PortRev(port));
-#if 0
+#ifdef NOISY_FDGC
 		fprintf(stderr, "GC'ing %srevealed port[fd] %d[%d]\n",
 			rev == 0 ? "un" : "",
 			port, fd);
@@ -335,7 +334,7 @@ void post_gc_fdports(void)
 		}
 	    }
 	}
-#if 0
+#ifdef NOISY_FDGC
     fputs("}", stderr); fflush(stderr);
 #endif
     }