diff --git a/.github/actions/restore-node/action.yml b/.github/actions/restore-node/action.yml
index effedbbc0f58..a1e17d50f60d 100644
--- a/.github/actions/restore-node/action.yml
+++ b/.github/actions/restore-node/action.yml
@@ -129,21 +129,28 @@ runs:
         if test -e ~/endo; then
           scripts/get-packed-versions.sh ~/endo | scripts/resolve-versions.sh
         fi
-        cp package.json package.json.orig
         yarn install
 
-        if cmp -s package.json.orig package.json; then
-          # We need to generate a yarn-installed.sum that matches the
-          # unmodified package.json.  As long as we don't explicitly
-          # `yarn install` anywhere other than in this action and in
-          # the bin/agd script, we should be able to reuse even
-          # Endo-overridden built caches successfully.
+        if ! cmp -s <(git cat-file blob HEAD:package.json) package.json; then
+          # In the event that the package.json has been modified by Endo
+          # replacements, We need to generate a yarn-installed.sum that matches
+          # the unmodified package.json.  As long as we don't explicitly `yarn
+          # install` anywhere other than in this action and in the bin/agd
+          # script, we should be able to reuse even Endo-overridden built caches
+          # successfully.
           git checkout HEAD -- package.json
         fi
-        rm package.json.orig
 
-        function findsha1() {
-          find ${1+"$@"} -print0 | xargs -0 sha1sum | sort +1 || true
+        function diffsha1() {
+          stamp=$1
+          shift
+          find ${1+"$@"} -exec sha1sum {} \; | sort +1 > "$stamp.new" || true
+          if test ! -s "$stamp.new" -a ! -e "$stamp"; then
+            echo "No dependencies found for $stamp" 1>&2
+            return 0
+          fi
+          diff -u "$stamp" "$stamp.new" || return 1
+          return 0
         }
 
         # Find the current list of package.jsons.
@@ -154,7 +161,7 @@ runs:
           sed -ne '/"location":/{ s/.*": "//; s!",.*!/package.json!; p; }')
 
         mkdir -p node_modules/.cache/agoric
-        findsha1 "${files[@]}" > node_modules/.cache/agoric/yarn-installed.sum
+        diffsha1 node_modules/.cache/agoric/yarn-installed.sum "${files[@]}"
 
         if test -e ~/endo; then
           # Stage the redirected `yarn install` consequences.
diff --git a/bin/agd b/bin/agd
index 35e412a79b3d..f111f7adde32 100755
--- a/bin/agd
+++ b/bin/agd
@@ -19,8 +19,16 @@ function fatal() {
   exit 1
 }
 
-function findsha1() {
-  find ${1+"$@"} -print0 | xargs -0 sha1sum | sort +1 || true
+function diffsha1() {
+  stamp=$1
+  shift
+  find ${1+"$@"} -exec sha1sum {} \; | sort +1 > "$stamp.new" || true
+  if test ! -s "$stamp.new" -a ! -e "$stamp"; then
+    echo "No dependencies found for $stamp" 1>&2
+    return 0
+  fi
+  diff -u "$stamp" "$stamp.new" || return 1
+  return 0
 }
 
 GVM_URL=${GVM_URL-https://github.com/devnw/gvm/releases/download/latest/gvm}
@@ -34,7 +42,9 @@ thisdir=$(cd "$(dirname -- "$real0")" >/dev/null && pwd -P)
 # shellcheck disable=SC1091
 source "$thisdir/../repoconfig.sh"
 
+NO_BUILD=${NO_BUILD-false}
 if test "${1-''}" = build; then
+  NO_BUILD=false
   BUILD_ONLY=true
   # Enable shell debugging.
   set -x
@@ -124,9 +134,7 @@ fi
     done < <(lazy_yarn -s workspaces info |
       sed -ne '/"location":/{ s/.*": "//; s!",.*!/package.json!; p; }')
 
-    findsha1 "${files[@]}" > "$sum.new" || true
-    diff -u "$sum" "$sum.new" || {
-      echo "$sum has changed"
+    diffsha1 "$sum" "${files[@]}" || { echo "$sum has changed"; $NO_BUILD; } || {
       rm -f "$sum" "$STAMPS/yarn-built"
       lazy_yarn install
       mv "$sum.new" "$sum"
@@ -142,12 +150,10 @@ fi
   fi
 
   sum=$STAMPS/golang-built.sum
-  findsha1 "$GOLANG_DIR" \( \
+  diffsha1 "$sum" "$GOLANG_DIR" \( \
     ! -name '*_test.go' -name '*.go' \
     -o -name '*.cc' \
-    -o -name 'go.*' \) > "$sum.new" || true
-  diff -u "$sum" "$sum.new" || {
-    echo "$GOLANG_DIR $sum has changed"
+    -o -name 'go.*' \) || { echo "$GOLANG_DIR $sum has changed"; $NO_BUILD; } || {
     rm -f "$sum"
     (
       # Run this build in another subshell in case we had to modify the path.
diff --git a/scripts/smoketest-binaries.sh b/scripts/smoketest-binaries.sh
index 126b7a60c256..3b866e382938 100755
--- a/scripts/smoketest-binaries.sh
+++ b/scripts/smoketest-binaries.sh
@@ -4,7 +4,7 @@
 
 binaries=( "agd version" "agoric -V" "ag-chain-cosmos version" )
 for binary in "${binaries[@]}"; do
-   echo "Checking $binary a"
+   echo "Checking $binary"
    $binary
    ec=$?
    if [[ $ec -ne 0 ]]; then