diff --git a/arvo/zuse.hoon b/arvo/zuse.hoon
index dc0adf7d2a..886594f21f 100644
--- a/arvo/zuse.hoon
+++ b/arvo/zuse.hoon
@@ -1013,11 +1013,12 @@
     [(awoe -.alt) (alot +.alt)]
   ::
   ++  auld                                          ::    auld:ez
-    |=  [gem=germ sab=saba]                         ::  construct merge
+    |=  [gem=germ who=ship des=desk sab=saba]       ::  construct merge
     ^-  (unit (unit nori))                          ::::::
     =+  ^=  viq  ^-  [p=@ud q=@ud r=waks]           ::  merge status
         =+  viq=(~(get by ang) [p.sab q.sab])       ::
         ?~(viq [0 0 ~] u.viq)                       ::
+    =.  sab  sab(s (skip s.sab (clen who des)))     ::
     =.  sab                                         ::
       ?:  =(q.viq p.r.sab)  sab                     ::  perfect motion
       ?>  (gth q.viq p.r.sab)                       ::  proper motion
@@ -1025,7 +1026,6 @@
         p.r  q.viq                                  ::
         s    (slag (sub q.viq p.r.sab) s.sab)       ::  remove excess
       ==                                            ::
-    =.  sab  sab(s (skip s.sab (clen p.sab q.sab))) ::
     ?~  s.sab  [~ ~]                                ::  up to date
     =+  ^=   mus  ^-  masu                          ::  sync square
         [p.sab q.sab [p.viq +(let)] [q.viq q.r.sab] r.viq]
@@ -1036,7 +1036,7 @@
         %+  skip
         %+  turn  (scag (sub let p.viq) hit)        ::  remove excess
         |=(a=frog q.a)
-        (clen p.sab q.sab)
+        (clen who des)
     =+  tig=(mang [arum r.viq tak kat] |=(* *(unit))) ::  moves
     ?^  tig
       =+  res=((hard ,[waks (list tako)]) u.tig)
diff --git a/main/bin/update.hoon b/main/bin/update.hoon
index 56c6167db2..1c6991642a 100644
--- a/main/bin/update.hoon
+++ b/main/bin/update.hoon
@@ -18,7 +18,7 @@
 =+  der=((hard dome) .^(%cv /(scot %p bos)/[des]/[wen]))
 =+  owr=((hard dome) .^(%cv /(scot %p who)/[des]/[wen]))
 =+  sab=`saba`[bos des [0 let.der] (flop (turn hit.der |=(a=frog q.a)))]
-=+  lum=(~(auld ze est owr) ?~(gem %fine -.gem) sab)
+=+  lum=(~(auld ze est owr) ?~(gem %fine -.gem) who des sab)
 ?~  lum
   ^-  gift
   [%la %leaf "{(trip des)} failed to merge, please rerun with a merge option"]
diff --git a/try/bin/merge.hoon b/try/bin/merge.hoon
index 2b088fb09a..c7c82c62f2 100644
--- a/try/bin/merge.hoon
+++ b/try/bin/merge.hoon
@@ -15,12 +15,14 @@
 =+  vsr=((hard dome) .^(%cv pes))
 =+  ves=((hard dome) .^(%cv pen))
 =+  ^=  sab  ^-  saba  :*
-    (need (slaw 'p' sen.pen))
-    den.pen
+    (need (slaw 'p' ses.pes))
+    des.pes
     [0 let.vsr]
     (flop (turn hit.vsr |=(a=frog q.a)))
     ==
-=+  lum=(~(auld ze est ves) ?~(gem %fine -.gem) sab)
+=+  ^=  lum
+    %-  ~(auld ze est ves)
+    [?~(gem %fine -.gem) (need (slaw 'p' sen.pen)) den.pen sab]
 ?~  lum
   ^-  gift
   :*  %la  %leaf