diff --git a/bin/box b/bin/box
index c6359f1..6a1daf5 100755
--- a/bin/box
+++ b/bin/box
@@ -1005,14 +1005,37 @@ cmd_expose() {
   incus network acl rule add box-isolate ingress action=allow \
     "destination=$ip/32" "destination_port=$port" protocol=tcp >/dev/null 2>&1 || true
 
+  # A VM's proxy device needs NAT mode — the plain userspace forkproxy is a
+  # container thing. NAT mode DNATs host:port → instance:port in netfilter, and
+  # it REQUIRES the instance's NIC to hold a static address, so pin the lease
+  # the box already has. Pinning also fixes the restart caveat: the exposure
+  # survives a reboot instead of pointing at a lease the box no longer owns.
+  local err; err="$(mktemp)"
+  if ! incus config device override "$inst" eth0 "ipv4.address=$ip" >/dev/null 2>"$err"; then
+    # Already overridden (a second exposure on the same box) is fine.
+    grep -qi 'already' "$err" || {
+      echo "box: could not pin the box's address (needed for a VM proxy):" >&2
+      sed 's/^/  /' "$err" >&2; rm -f "$err"
+      incus network acl rule remove box-isolate ingress action=allow \
+        "destination=$ip/32" "destination_port=$port" protocol=tcp >/dev/null 2>&1
+      die "expose failed"
+    }
+  fi
+
   if incus config device add "$inst" "$dev" proxy \
-       "listen=tcp:127.0.0.1:$hport" "connect=tcp:$ip:$port" bind=host >/dev/null; then
+       "listen=tcp:127.0.0.1:$hport" "connect=tcp:$ip:$port" \
+       bind=host nat=true >/dev/null 2>"$err"; then
+    rm -f "$err"
     echo "box: 127.0.0.1:$hport → $box:$port"
     echo "box: (the in-box server must listen on 0.0.0.0:$port, not only its own loopback)"
   else
+    # NEVER swallow incus's reason — the first cut of this verb died with a bare
+    # "could not add the proxy device" and told the drill nothing.
+    echo "box: incus refused the proxy device:" >&2
+    sed 's/^/  /' "$err" >&2; rm -f "$err"
     incus network acl rule remove box-isolate ingress action=allow \
       "destination=$ip/32" "destination_port=$port" protocol=tcp >/dev/null 2>&1
-    die "could not add the proxy device"
+    die "expose failed"
   fi
 }
 
diff --git a/drill/drill.sh b/drill/drill.sh
index 4b227c5..03413fa 100755
--- a/drill/drill.sh
+++ b/drill/drill.sh
@@ -57,9 +57,11 @@ inf()  { printf '        %s\n' "$*"; }
 phase(){ printf '\n\033[1m══ %s\033[0m\n' "$*"; }
 aud()  { audit+=("$*"); }                       # an answer for the #15 audit
 
-wait_box() {   # poll until exec answers (the VM agent can take a while), ~2 min
+wait_box() {   # poll until exec answers (the VM agent can take a while), ~4 min
+  # 2 min was too short: run 17's legacy box came up AFTER the window closed —
+  # the drill called it dead and then every migration check on it passed.
   local b="$1" _i
-  for _i in $(seq 1 60); do
+  for _i in $(seq 1 120); do
     box exec "$b" -- true >/dev/null 2>&1 && return 0
     sleep 2
   done
@@ -465,6 +467,16 @@ for t in codex grok; do
     else
       no "$t: '$bin --version' FAILED via exec — not installed, or not on exec's PATH (the claude template's #15 bug)"
       inf "PATH as exec sees it: $(timeout -k 5 20 box exec "$t" -- printenv PATH </dev/null 2>/dev/null)"
+      # Do not throw the evidence away — say WHAT the installer actually left.
+      # Do NOT throw the evidence away — say what the installer actually left
+      # behind, and what its own log said. Guessing at an upstream installer's
+      # layout is how this FAILed in the first place.
+      inf "anything named '$t' on disk:"
+      in_box "$t" sh -c "find /home /opt /usr/local /usr/bin -maxdepth 4 \\( -type f -o -type l \\) -iname '*$t*' 2>/dev/null | head -8" \
+        | sed 's/^/          /'
+      inf "what its cloud-init said:"
+      in_box "$t" sh -c "grep -iE '$t|install' /var/log/cloud-init-output.log 2>/dev/null | tail -8" \
+        | sed 's/^/          /'
     fi
     box rm "$t" --force >/dev/null 2>&1 && ok "$t box removed" || no "$t: could not remove"
   else
diff --git a/host/migrate-host.sh b/host/migrate-host.sh
index c4b2968..688e920 100644
--- a/host/migrate-host.sh
+++ b/host/migrate-host.sh
@@ -47,7 +47,17 @@ require_new_stack() {
   incus profile show box-net >/dev/null 2>&1 || die "box-net profile does not exist — run host/setup-host.sh first"
 }
 
-legacy_boxes() { incus list "user.claudebox=1" -f csv -c n 2>/dev/null; }
+# A box is LEGACY only if it still carries the old tag and has NOT been
+# re-homed. Counting every user.claudebox=1 box was a bug: re-homing ADDS
+# user.box=1 without removing the old tag, so --retire-legacy saw its own
+# migrated boxes as un-migrated and refused forever.
+legacy_boxes() {
+  local b
+  for b in $(incus list "user.claudebox=1" -f csv -c n 2>/dev/null); do
+    [ "$(incus config get "$b" user.box 2>/dev/null)" = 1 ] && continue   # already re-homed
+    echo "$b"
+  done
+}
 
 # Re-home one box. Legacy boxes are all claude boxes (the only template the old
 # tool minted), so the new metadata is the claude template's.
@@ -86,6 +96,12 @@ rehome_one() {
   done
   [ -n "$ip" ] || { warn "$b: never got a 10.88 address after restart — re-home INCOMPLETE, inspect: incus console $b"; return 1; }
   if incus exec "$b" -- getent hosts deb.debian.org </dev/null >/dev/null 2>&1; then
+    # LAST, and only once the move is VERIFIED: drop the legacy tag. Until this
+    # point the box wears both tags, so a failure anywhere above leaves it a
+    # valid box under one name or the other — never orphaned. Now it is simply
+    # a box, and --retire-legacy can see the old stack is empty.
+    incus config unset "$b" user.claudebox >/dev/null 2>&1 \
+      || warn "$b: migrated, but the legacy tag could not be removed — retire-legacy will still see it"
     say "$b re-homed: on boxnet ($ip), resolves + reachable, authed state preserved"
     return 0
   fi
diff --git a/templates/grok/user-data.yaml b/templates/grok/user-data.yaml
index 535e5d0..1abbdec 100644
--- a/templates/grok/user-data.yaml
+++ b/templates/grok/user-data.yaml
@@ -50,10 +50,31 @@ runcmd:
   # binary under the invoking user's home, so run it AS grok, not root.
   - sudo -u grok bash -lc 'curl -fsSL https://x.ai/cli/install.sh | bash'
   # 'box exec <b> -- grok-build …' runs a NON-interactive shell that reads no
-  # rc files. Find whatever the installer dropped and symlink it onto the
-  # system PATH — the same fix the claude template needed. If the installer's
-  # binary name changes upstream, this glob is the one line to update.
+  # rc files, so whatever the installer dropped must be symlinked onto the
+  # system PATH — the same fix the claude template needed (#15).
+  #
+  # The FIRST cut of this hunted only for a regular file named exactly
+  # 'grok-build' under /home/grok, and found nothing: the drill's grok box
+  # minted fine and then failed '--version'. Two lessons, both applied here:
+  # an installer's drop may be a SYMLINK (so -type f alone misses it), and its
+  # binary name is upstream's to choose (so try the plausible names, and any
+  # 'grok*' executable, before giving up). Then SAY what was found — a silent
+  # miss is what cost the last run.
   - |
-    bin="$(find /home/grok -maxdepth 4 -type f -name 'grok-build' 2>/dev/null | head -1)"
-    [ -n "$bin" ] && ln -sf "$bin" /usr/local/bin/grok-build || echo "grok-build binary not found post-install — check x.ai/cli install layout" >&2
+    bin=""
+    for cand in grok-build grok; do
+      for d in /home/grok/.local/bin /home/grok/.grok/bin /home/grok/bin /usr/local/bin /opt; do
+        [ -x "$d/$cand" ] && { bin="$d/$cand"; break 2; }
+      done
+    done
+    [ -n "$bin" ] || bin="$(find /home/grok /opt -maxdepth 5 \( -type f -o -type l \) -iname 'grok*' -perm -u+x 2>/dev/null | head -1)"
+    if [ -n "$bin" ]; then
+      ln -sf "$bin" /usr/local/bin/grok-build
+      ln -sf "$bin" /usr/local/bin/grok
+      echo "grok: linked $bin -> /usr/local/bin/{grok-build,grok}"
+    else
+      echo "grok: NO BINARY FOUND after x.ai/cli/install.sh — the box is up but the CLI is not on PATH." >&2
+      echo "grok: what the installer left under /home/grok:" >&2
+      find /home/grok -maxdepth 4 \( -type f -o -type l \) -perm -u+x 2>/dev/null | head -20 >&2
+    fi
   - echo 'export PATH="$HOME/.local/bin:$PATH"' >> /home/grok/.bashrc