diff --git a/pkg/noun/v1/allocate.c b/pkg/noun/v1/allocate.c
index 4192fedd20..b8da1684e6 100644
--- a/pkg/noun/v1/allocate.c
+++ b/pkg/noun/v1/allocate.c
@@ -28,7 +28,7 @@ u3a_v1_rewritten_noun(u3_noun som)
   if ( c3y == u3a_is_cat(som) ) {
     return som;
   }
-  u3_post som_p = u3a_v1_rewritten(u3a_v1_to_off(som));
+  u3_post som_p = u3a_rewritten(u3a_v1_to_off(som));
 
   if ( c3y == u3a_is_pug(som) ) {
     som_p = u3a_v1_to_pug(som_p);  //  XX alias?
@@ -60,8 +60,8 @@ u3a_v1_rewrite_compact(void)
   u3R->bug.mer = u3a_v1_rewritten_noun(u3R->bug.mer);
   u3R->pro.don = u3a_v1_rewritten_noun(u3R->pro.don);
   u3R->pro.day = u3a_v1_rewritten_noun(u3R->pro.day);
-  u3R->pro.trace = u3a_v1_rewritten_noun(u3R->pro.trace);
-  u3R->cax.har_p = u3a_v1_rewritten(u3R->cax.har_p);
+  u3R->pro.trace = u3a_rewritten_noun(u3R->pro.trace);
+  u3R->cax.har_p = u3a_rewritten(u3R->cax.har_p);
 }
 void
 u3a_v1_rewrite_noun(u3_noun som)
diff --git a/pkg/noun/v1/hashtable.c b/pkg/noun/v1/hashtable.c
index 1a2cb6b6c9..1018201abb 100644
--- a/pkg/noun/v1/hashtable.c
+++ b/pkg/noun/v1/hashtable.c
@@ -10,20 +10,20 @@
 #include "xtract.h"
 
 
-/* _ch_popcount(): number of bits set in word.  A standard intrinsic.
-**             NB: copy of _ch_popcount in pkg/noun/hashtable.c
+/* _ch_v1_popcount(): number of bits set in word.  A standard intrinsic.
+**             NB: copy of _ch_v1_popcount in pkg/noun/hashtable.c
 */
 static c3_w
-_ch_popcount(c3_w num_w)
+_ch_v1_popcount(c3_w num_w)
 {
   return __builtin_popcount(num_w);
 }
 
-/* _ch_free_buck(): free bucket
-**              NB: copy of _ch_free_buck in pkg/noun/hashtable.c
+/* _ch_v1_free_buck(): free bucket
+**              NB: copy of _ch_v1_free_buck in pkg/noun/hashtable.c
 */
 static void
-_ch_free_buck(u3h_buck* hab_u)
+_ch_v1_free_buck(u3h_buck* hab_u)
 {
   c3_w i_w;
 
@@ -33,12 +33,12 @@ _ch_free_buck(u3h_buck* hab_u)
   u3a_wfree(hab_u);
 }
 
-/* _ch_free_node(): free node.
+/* _ch_v1_free_node(): free node.
 */
 static void
-_ch_free_node(u3h_node* han_u, c3_w lef_w)
+_ch_v1_free_node(u3h_node* han_u, c3_w lef_w)
 {
-  c3_w len_w = _ch_popcount(han_u->map_w);
+  c3_w len_w = _ch_v1_popcount(han_u->map_w);
   c3_w i_w;
 
   lef_w -= 5;
@@ -53,9 +53,9 @@ _ch_free_node(u3h_node* han_u, c3_w lef_w)
       void* hav_v = u3h_v1_slot_to_node(sot_w);
 
       if ( 0 == lef_w ) {
-        _ch_free_buck(hav_v);
+        _ch_v1_free_buck(hav_v);
       } else {
-        _ch_free_node(hav_v, lef_w);
+        _ch_v1_free_node(hav_v, lef_w);
       }
     }
   }
@@ -79,17 +79,17 @@ u3h_v1_free(u3p(u3h_root) har_p)
     else if ( _(u3h_slot_is_node(sot_w)) ) {
       u3h_node* han_u = u3h_slot_to_node(sot_w);
 
-      _ch_free_node(han_u, 25);
+      _ch_v1_free_node(han_u, 25);
     }
   }
   u3a_free(har_u);
 }
 
-/* _ch_walk_buck(): walk bucket for gc.
-**              NB: copy of _ch_walk_buck in pkg/noun/hashtable.c
+/* _ch_v1_walk_buck(): walk bucket for gc.
+**              NB: copy of _ch_v1_walk_buck in pkg/noun/hashtable.c
 */
 static void
-_ch_walk_buck(u3h_buck* hab_u, void (*fun_f)(u3_noun, void*), void* wit)
+_ch_v1_walk_buck(u3h_buck* hab_u, void (*fun_f)(u3_noun, void*), void* wit)
 {
   c3_w i_w;
 
@@ -98,12 +98,12 @@ _ch_walk_buck(u3h_buck* hab_u, void (*fun_f)(u3_noun, void*), void* wit)
   }
 }
 
-/* _ch_walk_node(): walk node for gc.
+/* _ch_v1_walk_node(): walk node for gc.
 */
 static void
-_ch_walk_node(u3h_node* han_u, c3_w lef_w, void (*fun_f)(u3_noun, void*), void* wit)
+_ch_v1_walk_node(u3h_node* han_u, c3_w lef_w, void (*fun_f)(u3_noun, void*), void* wit)
 {
-  c3_w len_w = _ch_popcount(han_u->map_w);
+  c3_w len_w = _ch_v1_popcount(han_u->map_w);
   c3_w i_w;
 
   lef_w -= 5;
@@ -120,9 +120,9 @@ _ch_walk_node(u3h_node* han_u, c3_w lef_w, void (*fun_f)(u3_noun, void*), void*
       void* hav_v = u3h_slot_to_node(sot_w);
 
       if ( 0 == lef_w ) {
-        _ch_walk_buck(hav_v, fun_f, wit);
+        _ch_v1_walk_buck(hav_v, fun_f, wit);
       } else {
-        _ch_walk_node(hav_v, lef_w, fun_f, wit);
+        _ch_v1_walk_node(hav_v, lef_w, fun_f, wit);
       }
     }
   }
@@ -150,15 +150,15 @@ u3h_v1_walk_with(u3p(u3h_root) har_p,
     else if ( _(u3h_slot_is_node(sot_w)) ) {
       u3h_node* han_u = u3h_slot_to_node(sot_w);
 
-      _ch_walk_node(han_u, 25, fun_f, wit);
+      _ch_v1_walk_node(han_u, 25, fun_f, wit);
     }
   }
 }
 
-/* _ch_v1_walk_plain(): use plain u3_noun fun_f for each node
+/* _ch_v1_v1_walk_plain(): use plain u3_noun fun_f for each node
  */
 static void
-_ch_v1_walk_plain(u3_noun kev, void* wit)
+_ch_v1_v1_walk_plain(u3_noun kev, void* wit)
 {
   void (*fun_f)(u3_noun) = wit;
   fun_f(kev);
@@ -169,13 +169,13 @@ _ch_v1_walk_plain(u3_noun kev, void* wit)
 void
 u3h_v1_walk(u3p(u3h_root) har_p, void (*fun_f)(u3_noun))
 {
-  u3h_v1_walk_with(har_p, _ch_v1_walk_plain, fun_f);
+  u3h_v1_walk_with(har_p, _ch_v1_v1_walk_plain, fun_f);
 }
 
-/* _ch_rewrite_buck(): rewrite buck for compaction.
+/* _ch_v1_rewrite_buck(): rewrite buck for compaction.
 */
 void
-_ch_rewrite_buck(u3h_buck* hab_u)
+_ch_v1_rewrite_buck(u3h_buck* hab_u)
 {
   if ( c3n == u3a_rewrite_ptr(hab_u) ) return;
   c3_w i_w;
@@ -187,14 +187,14 @@ _ch_rewrite_buck(u3h_buck* hab_u)
   }
 }
 
-/* _ch_rewrite_node(): rewrite node for compaction.
+/* _ch_v1_rewrite_node(): rewrite node for compaction.
 */
 void
-_ch_rewrite_node(u3h_node* han_u, c3_w lef_w)
+_ch_v1_rewrite_node(u3h_node* han_u, c3_w lef_w)
 {
   if ( c3n == u3a_rewrite_ptr(han_u) ) return;
 
-  c3_w len_w = _ch_popcount(han_u->map_w);
+  c3_w len_w = _ch_v1_popcount(han_u->map_w);
   c3_w i_w;
 
   lef_w -= 5;
@@ -210,14 +210,14 @@ _ch_rewrite_node(u3h_node* han_u, c3_w lef_w)
     }
     else {
       void* hav_v = u3h_v1_slot_to_node(sot_w);
-      u3h_node* nod_u = u3to(u3h_node, u3a_v1_rewritten(u3of(u3h_node,hav_v)));
+      u3h_node* nod_u = u3to(u3h_node, u3a_rewritten(u3of(u3h_node,hav_v)));
 
       han_u->sot_w[i_w] = u3h_v1_node_to_slot(nod_u);
 
       if ( 0 == lef_w ) {
-        _ch_rewrite_buck(hav_v);
+        _ch_v1_rewrite_buck(hav_v);
       } else {
-        _ch_rewrite_node(hav_v, lef_w);
+        _ch_v1_rewrite_node(hav_v, lef_w);
       }
     }
   }
@@ -244,11 +244,11 @@ u3h_v1_rewrite(u3p(u3h_root) har_p)
     }
     else if ( _(u3h_slot_is_node(sot_w)) ) {
       u3h_node* han_u = u3h_v1_slot_to_node(sot_w);
-      u3h_node* nod_u = u3to(u3h_node, u3a_v1_rewritten(u3of(u3h_node,han_u)));
+      u3h_node* nod_u = u3to(u3h_node, u3a_rewritten(u3of(u3h_node,han_u)));
 
       har_u->sot_w[i_w] = u3h_v1_node_to_slot(nod_u);
 
-      _ch_rewrite_node(han_u, 25);
+      _ch_v1_rewrite_node(han_u, 25);
     }
   }
 }
diff --git a/pkg/noun/v1/jets.c b/pkg/noun/v1/jets.c
index da57d7a4f9..f84c856fb1 100644
--- a/pkg/noun/v1/jets.c
+++ b/pkg/noun/v1/jets.c
@@ -11,24 +11,24 @@
 /**  Data structures.
 **/
 
-/* _cj_hank: cached hook information.
-**       NB: copy of _cj_hank from pkg/noun/jets.c
+/* _cj_v1_hank: cached hook information.
+**       NB: copy of _cj_v1_hank from pkg/noun/jets.c
  */
 typedef struct {
   u3_weak  hax;                     //  axis of hooked inner core
   u3j_site sit_u;                   //  call-site data
-} _cj_hank;
+} _cj_v1_hank;
 
 /**  Functions.
 **/
 
-/* _cj_free_hank(): free an entry from the hank cache.
-**              NB: copy of _cj_free_hank() from pkg/noun/jets.c
+/* _cj_v1_free_hank(): free an entry from the hank cache.
+**              NB: copy of _cj_v1_free_hank() from pkg/noun/jets.c
 */
 static void
-_cj_free_hank(u3_noun kev)
+_cj_v1_free_hank(u3_noun kev)
 {
-  _cj_hank* han_u = u3to(_cj_hank, u3t(kev));
+  _cj_v1_hank* han_u = u3to(_cj_v1_hank, u3t(kev));
   if ( u3_none != han_u->hax ) {
     u3z(han_u->hax);
     u3j_site_lose(&(han_u->sit_u));
@@ -51,7 +51,7 @@ u3j_v1_reclaim(void)
 
   //  clear the jet hank cache
   //
-  u3h_v1_walk(u3R->jed.han_p, _cj_free_hank);
+  u3h_v1_walk(u3R->jed.han_p, _cj_v1_free_hank);
   u3h_v1_free(u3R->jed.han_p);
   u3R->jed.han_p = u3h_new();
 }
diff --git a/pkg/noun/v1/nock.c b/pkg/noun/v1/nock.c
index ffd390d969..f701e05b22 100644
--- a/pkg/noun/v1/nock.c
+++ b/pkg/noun/v1/nock.c
@@ -59,3 +59,23 @@ u3n_v1_free()
   u3h_v1_walk(har_p, _n_feb);
   u3h_v1_free(har_p);
 }
+
+/* u3n_v1_rewrite_compact(): rewrite the bytecode cache for compaction.
+ *
+ * NB: u3R->byc.har_p *must* be cleared (currently via u3n_v1_reclaim above),
+ * since it contains things that look like nouns but aren't.
+ * Specifically, it contains "cells" where the tail is a
+ * pointer to a u3a_malloc'ed block that contains loom pointers.
+ *
+ * You should be able to walk this with u3h_walk and rewrite the
+ * pointers, but you need to be careful to handle that u3a_malloc
+ * pointers can't be turned into a box by stepping back two words. You
+ * must step back one word to get the padding, step then step back that
+ * many more words (plus one?).
+ */
+void
+u3n_v1_rewrite_compact()
+{
+  u3h_v1_rewrite(u3R->byc.har_p);
+  u3R->byc.har_p = u3a_rewritten(u3R->byc.har_p);
+}
diff --git a/pkg/noun/v2/allocate.c b/pkg/noun/v2/allocate.c
index d30629487a..a6ac5f3604 100644
--- a/pkg/noun/v2/allocate.c
+++ b/pkg/noun/v2/allocate.c
@@ -67,8 +67,8 @@ u3a_v2_rewrite_compact(void)
   u3R->bug.mer = u3a_v2_rewritten_noun(u3R->bug.mer);
   u3R->pro.don = u3a_v2_rewritten_noun(u3R->pro.don);
   u3R->pro.day = u3a_v2_rewritten_noun(u3R->pro.day);
-  u3R->pro.trace = u3a_v2_rewritten_noun(u3R->pro.trace);
-  u3R->cax.har_p = u3a_v2_rewritten(u3R->cax.har_p);
+  u3R->pro.trace = u3a_rewritten_noun(u3R->pro.trace);
+  u3R->cax.har_p = u3a_rewritten(u3R->cax.har_p);
 }
 
 void
diff --git a/pkg/noun/v2/hashtable.c b/pkg/noun/v2/hashtable.c
index 47dadc5311..6593d9a299 100644
--- a/pkg/noun/v2/hashtable.c
+++ b/pkg/noun/v2/hashtable.c
@@ -11,20 +11,20 @@
 #include "retrieve.h"
 #include "xtract.h"
 
-/* _ch_popcount(): number of bits set in word.  A standard intrinsic.
-**             NB: copy of _ch_popcount in pkg/noun/hashtable.c
+/* _ch_v2_popcount(): number of bits set in word.  A standard intrinsic.
+**             NB: copy of _ch_v2_popcount in pkg/noun/hashtable.c
 */
 static c3_w
-_ch_popcount(c3_w num_w)
+_ch_v2_popcount(c3_w num_w)
 {
   return __builtin_popcount(num_w);
 }
 
-/* _ch_free_buck(): free bucket
-**              NB: copy of _ch_free_buck in pkg/noun/hashtable.c
+/* _ch_v2_free_buck(): free bucket
+**              NB: copy of _ch_v2_free_buck in pkg/noun/hashtable.c
 */
 static void
-_ch_free_buck(u3h_buck* hab_u)
+_ch_v2_free_buck(u3h_buck* hab_u)
 {
   c3_w i_w;
 
@@ -34,12 +34,12 @@ _ch_free_buck(u3h_buck* hab_u)
   u3a_wfree(hab_u);
 }
 
-/* _ch_free_node(): free node.
+/* _ch_v2_free_node(): free node.
 */
 static void
-_ch_free_node(u3h_node* han_u, c3_w lef_w)
+_ch_v2_free_node(u3h_node* han_u, c3_w lef_w)
 {
-  c3_w len_w = _ch_popcount(han_u->map_w);
+  c3_w len_w = _ch_v2_popcount(han_u->map_w);
   c3_w i_w;
 
   lef_w -= 5;
@@ -55,9 +55,9 @@ _ch_free_node(u3h_node* han_u, c3_w lef_w)
       void* hav_v = u3h_v2_slot_to_node(sot_w);
 
       if ( 0 == lef_w ) {
-        _ch_free_buck(hav_v);
+        _ch_v2_free_buck(hav_v);
       } else {
-        _ch_free_node(hav_v, lef_w);
+        _ch_v2_free_node(hav_v, lef_w);
       }
     }
   }
@@ -81,17 +81,17 @@ u3h_v2_free(u3p(u3h_root) har_p)
     else if ( _(u3h_slot_is_node(sot_w)) ) {
       u3h_node* han_u = u3h_v2_slot_to_node(sot_w);
 
-      _ch_free_node(han_u, 25);
+      _ch_v2_free_node(han_u, 25);
     }
   }
   u3a_wfree(har_u);
 }
 
-/* _ch_walk_buck(): walk bucket for gc.
-**              NB: copy of _ch_walk_buck in pkg/noun/hashtable.c
+/* _ch_v2_walk_buck(): walk bucket for gc.
+**              NB: copy of _ch_v2_walk_buck in pkg/noun/hashtable.c
 */
 static void
-_ch_walk_buck(u3h_buck* hab_u, void (*fun_f)(u3_noun, void*), void* wit)
+_ch_v2_walk_buck(u3h_buck* hab_u, void (*fun_f)(u3_noun, void*), void* wit)
 {
   c3_w i_w;
 
@@ -100,12 +100,12 @@ _ch_walk_buck(u3h_buck* hab_u, void (*fun_f)(u3_noun, void*), void* wit)
   }
 }
 
-/* _ch_walk_node(): walk node for gc.
+/* _ch_v2_walk_node(): walk node for gc.
 */
 static void
-_ch_walk_node(u3h_node* han_u, c3_w lef_w, void (*fun_f)(u3_noun, void*), void* wit)
+_ch_v2_walk_node(u3h_node* han_u, c3_w lef_w, void (*fun_f)(u3_noun, void*), void* wit)
 {
-  c3_w len_w = _ch_popcount(han_u->map_w);
+  c3_w len_w = _ch_v2_popcount(han_u->map_w);
   c3_w i_w;
 
   lef_w -= 5;
@@ -122,9 +122,9 @@ _ch_walk_node(u3h_node* han_u, c3_w lef_w, void (*fun_f)(u3_noun, void*), void*
       void* hav_v = u3h_v2_slot_to_node(sot_w);
 
       if ( 0 == lef_w ) {
-        _ch_walk_buck(hav_v, fun_f, wit);
+        _ch_v2_walk_buck(hav_v, fun_f, wit);
       } else {
-        _ch_walk_node(hav_v, lef_w, fun_f, wit);
+        _ch_v2_walk_node(hav_v, lef_w, fun_f, wit);
       }
     }
   }
@@ -152,15 +152,15 @@ u3h_v2_walk_with(u3p(u3h_root) har_p,
     else if ( _(u3h_slot_is_node(sot_w)) ) {
       u3h_node* han_u = u3h_v2_slot_to_node(sot_w);
 
-      _ch_walk_node(han_u, 25, fun_f, wit);
+      _ch_v2_walk_node(han_u, 25, fun_f, wit);
     }
   }
 }
 
-/* _ch_walk_plain(): use plain u3_noun fun_f for each node
+/* _ch_v2_walk_plain(): use plain u3_noun fun_f for each node
  */
 static void
-_ch_walk_plain(u3_noun kev, void* wit)
+_ch_v2_walk_plain(u3_noun kev, void* wit)
 {
   void (*fun_f)(u3_noun) = wit;
   fun_f(kev);
@@ -171,13 +171,13 @@ _ch_walk_plain(u3_noun kev, void* wit)
 void
 u3h_v2_walk(u3p(u3h_root) har_p, void (*fun_f)(u3_noun))
 {
-  u3h_v2_walk_with(har_p, _ch_walk_plain, fun_f);
+  u3h_v2_walk_with(har_p, _ch_v2_walk_plain, fun_f);
 }
 
-/* _ch_rewrite_buck(): rewrite buck for compaction.
+/* _ch_v2_rewrite_buck(): rewrite buck for compaction.
 */
 void
-_ch_rewrite_buck(u3h_buck* hab_u)
+_ch_v2_rewrite_buck(u3h_buck* hab_u)
 {
   if ( c3n == u3a_rewrite_ptr(hab_u) ) return;
   c3_w i_w;
@@ -189,14 +189,14 @@ _ch_rewrite_buck(u3h_buck* hab_u)
   }
 }
 
-/* _ch_rewrite_node(): rewrite node for compaction.
+/* _ch_v2_rewrite_node(): rewrite node for compaction.
 */
 void
-_ch_rewrite_node(u3h_node* han_u, c3_w lef_w)
+_ch_v2_rewrite_node(u3h_node* han_u, c3_w lef_w)
 {
   if ( c3n == u3a_rewrite_ptr(han_u) ) return;
 
-  c3_w len_w = _ch_popcount(han_u->map_w);
+  c3_w len_w = _ch_v2_popcount(han_u->map_w);
   c3_w i_w;
 
   lef_w -= 5;
@@ -212,7 +212,7 @@ _ch_rewrite_node(u3h_node* han_u, c3_w lef_w)
     }
     else {
       void* hav_v = u3h_v1_slot_to_node(sot_w);
-      u3h_node* nod_u = u3to(u3h_node, u3a_v1_rewritten(u3of(u3h_node,hav_v)));
+      u3h_node* nod_u = u3to(u3h_node, u3a_rewritten(u3of(u3h_node,hav_v)));
 
       if (u3C.migration_state == MIG_REWRITE_COMPRESSED)
         u3C.vits_w = 1;
@@ -223,9 +223,9 @@ _ch_rewrite_node(u3h_node* han_u, c3_w lef_w)
         u3C.vits_w = 0;
 
       if ( 0 == lef_w ) {
-        _ch_rewrite_buck(hav_v);
+        _ch_v2_rewrite_buck(hav_v);
       } else {
-        _ch_rewrite_node(hav_v, lef_w);
+        _ch_v2_rewrite_node(hav_v, lef_w);
       }
     }
   }
@@ -263,7 +263,7 @@ u3h_v2_rewrite(u3p(u3h_root) har_p)
       if (u3C.migration_state == MIG_REWRITE_COMPRESSED)
         u3C.vits_w = 0;
 
-      _ch_rewrite_node(han_u, 25);
+      _ch_v2_rewrite_node(han_u, 25);
     }
   }
 }
diff --git a/pkg/noun/v2/jets.c b/pkg/noun/v2/jets.c
index 840a8cbfe2..080f6e9660 100644
--- a/pkg/noun/v2/jets.c
+++ b/pkg/noun/v2/jets.c
@@ -11,24 +11,24 @@
 /**  Data structures.
 **/
 
-/* _cj_hank: cached hook information.
-**       NB: copy of _cj_hank from pkg/noun/jets.c
+/* _cj_v2_hank: cached hook information.
+**       NB: copy of _cj_v2_hank from pkg/noun/jets.c
  */
 typedef struct {
   u3_weak  hax;                     //  axis of hooked inner core
   u3j_site sit_u;                   //  call-site data
-} _cj_hank;
+} _cj_v2_hank;
 
 /**  Functions.
 **/
 
-/* _cj_free_hank(): free an entry from the hank cache.
-**              NB: copy of _cj_free_hank() from pkg/noun/jets.c
+/* _cj_v2_free_hank(): free an entry from the hank cache.
+**              NB: copy of _cj_v2_free_hank() from pkg/noun/jets.c
 */
 static void
-_cj_free_hank(u3_noun kev)
+_cj_v2_free_hank(u3_noun kev)
 {
-  _cj_hank* han_u = u3to(_cj_hank, u3t(kev));
+  _cj_v2_hank* han_u = u3to(_cj_v2_hank, u3t(kev));
   if ( u3_none != han_u->hax ) {
     u3z(han_u->hax);
     u3j_site_lose(&(han_u->sit_u));
@@ -51,7 +51,7 @@ u3j_v2_reclaim(void)
 
   //  clear the jet hank cache
   //
-  u3h_v2_walk(u3R->jed.han_p, _cj_free_hank);
+  u3h_v2_walk(u3R->jed.han_p, _cj_v2_free_hank);
   u3h_v2_free(u3R->jed.han_p);
   u3R->jed.han_p = u3h_new();
 }
diff --git a/pkg/noun/v2/manage.c b/pkg/noun/v2/manage.c
index 79a694c851..a01a29b46f 100644
--- a/pkg/noun/v2/manage.c
+++ b/pkg/noun/v2/manage.c
@@ -190,7 +190,7 @@ u3m_v2_migrate()
   /* only home road migration is supported */
   c3_dessert((uintptr_t)u3H == (uintptr_t)u3R);
 
-  fprintf(stderr, "loom: pointer compression migration running...");
+  fprintf(stderr, "loom: pointer compression migration running...\r\n");
 
   /* packing first simplifies migration logic and minimizes required buffer space */
   //  XX determine if we need to version this for the v2 migration
diff --git a/pkg/noun/v2/nock.c b/pkg/noun/v2/nock.c
index e2e2a36651..d476a394ce 100644
--- a/pkg/noun/v2/nock.c
+++ b/pkg/noun/v2/nock.c
@@ -59,3 +59,23 @@ u3n_v2_free()
   u3h_v2_walk(har_p, _n_feb);
   u3h_v2_free(har_p);
 }
+
+/* u3n_v2_rewrite_compact(): rewrite the bytecode cache for compaction.
+ *
+ * NB: u3R->byc.har_p *must* be cleared (currently via u3n_v2_reclaim above),
+ * since it contains things that look like nouns but aren't.
+ * Specifically, it contains "cells" where the tail is a
+ * pointer to a u3a_malloc'ed block that contains loom pointers.
+ *
+ * You should be able to walk this with u3h_walk and rewrite the
+ * pointers, but you need to be careful to handle that u3a_malloc
+ * pointers can't be turned into a box by stepping back two words. You
+ * must step back one word to get the padding, step then step back that
+ * many more words (plus one?).
+ */
+void
+u3n_v2_rewrite_compact()
+{
+  u3h_v2_rewrite(u3R->byc.har_p);
+  u3R->byc.har_p = u3a_rewritten(u3R->byc.har_p);
+}