diff --git a/racket/src/racket/src/eval.c b/racket/src/racket/src/eval.c
index 3e61decd80..c02a180cf5 100644
--- a/racket/src/racket/src/eval.c
+++ b/racket/src/racket/src/eval.c
@@ -6100,7 +6100,7 @@ static void mark_pruned_prefixes(struct NewGC *gc) XFORM_SKIP_PROC
   if (scheme_prefix_finalize != (Scheme_Prefix *)0x1) {
     Scheme_Prefix *pf = scheme_prefix_finalize, *next;
     Scheme_Object *clo;
-    int i, *use_bits, maxpos, inc_fixup_mode;
+    int i, *use_bits, maxpos;
     
     scheme_prefix_finalize = (Scheme_Prefix *)0x1;
     while (pf != (Scheme_Prefix *)0x1) {
@@ -6155,24 +6155,17 @@ static void mark_pruned_prefixes(struct NewGC *gc) XFORM_SKIP_PROC
       /* Fix up closures that reference this prefix: */
       clo = (Scheme_Object *)GC_resolve2(pf->fixup_chain, gc);
       pf->fixup_chain = NULL;
-      inc_fixup_mode = SCHEME_PREFIX_FLAGS(pf) & 0x1;
       while (clo) {
         Scheme_Object *next;
-        if (inc_fixup_mode) {
-          next = ((Scheme_Object **)clo)[1];
-          clo = ((Scheme_Object **)clo)[0];
-        }
         if (SCHEME_TYPE(clo) == scheme_closure_type) {
           Scheme_Closure *cl = (Scheme_Closure *)clo;
           int closure_size = ((Scheme_Closure_Data *)GC_resolve2(cl->code, gc))->closure_size;
-          if (!inc_fixup_mode)
-            next = cl->vals[closure_size - 1];
+          next = cl->vals[closure_size - 1];
           cl->vals[closure_size-1] = (Scheme_Object *)pf;
         } else if (SCHEME_TYPE(clo) == scheme_native_closure_type) {
           Scheme_Native_Closure *cl = (Scheme_Native_Closure *)clo;
           int closure_size = ((Scheme_Native_Closure_Data *)GC_resolve2(cl->code, gc))->closure_size;
-          if (!inc_fixup_mode)
-            next = cl->vals[closure_size - 1];
+          next = cl->vals[closure_size - 1];
           cl->vals[closure_size-1] = (Scheme_Object *)pf;
         } else {
           MZ_ASSERT(0);
@@ -6180,7 +6173,7 @@ static void mark_pruned_prefixes(struct NewGC *gc) XFORM_SKIP_PROC
         }
         clo = (Scheme_Object *)GC_resolve2(next, gc);
       }
-      if (inc_fixup_mode)
+      if (SCHEME_PREFIX_FLAGS(pf) & 0x1)
         SCHEME_PREFIX_FLAGS(pf) -= 0x1;
 
       /* Next */
diff --git a/racket/src/racket/src/mzclpf_post.inc b/racket/src/racket/src/mzclpf_post.inc
index 2bfd7f7182..3a1a642957 100644
--- a/racket/src/racket/src/mzclpf_post.inc
+++ b/racket/src/racket/src/mzclpf_post.inc
@@ -41,19 +41,15 @@
       mark_stxes = 0;
 
       /* Add this closure to the chain to be repaired when the
-         prefix is marked (and potentially moved): */
-      if ((gc_mode == GC_CURRENT_MODE_INCREMENTAL) || (SCHEME_PREFIX_FLAGS(pf) & 0x1)) {
-        /* Can't steal closure slot for this purpose, since the
-           slot is still in use until a full collection finishes */
-        Scheme_Object **pr;
-        pr = (Scheme_Object **)GC_malloc_for_incremental(2 * sizeof(Scheme_Object *));
-        pr[0] = (Scheme_Object *)c;
-        pr[1] = (Scheme_Object *)pf->fixup_chain;
-        pf->fixup_chain = (Scheme_Object *)pr;
-        SCHEME_PREFIX_FLAGS(pf) |= 0x1;
-      } else {
+         prefix is marked and potentially moved; if we're here
+         in incremental mode, though, the prefix won't be moved: */
+      if (gc_mode != GC_CURRENT_MODE_INCREMENTAL) {
         c->vals[closure_size - 1] = pf->fixup_chain;
         pf->fixup_chain = (Scheme_Object *)c;
+      } else {
+        /* Mark the prefix as reached in incremental mode, which
+           triggers special handling for bakpointers */
+        SCHEME_PREFIX_FLAGS(pf) |= 0x1;
       }
 
       /* Mark just the elements of the prefix that are (newly) used: */