diff --git a/deploy/arm64-installer/upgrade.sh b/deploy/arm64-installer/upgrade.sh
index eb5e35b..b820105 100755
--- a/deploy/arm64-installer/upgrade.sh
+++ b/deploy/arm64-installer/upgrade.sh
@@ -11,10 +11,11 @@ usage() {
   cat <<'USAGE'
 Usage: ./upgrade.sh [--reuse-env-from /path/to/.env] [--keep-reused-image]
 
-By default, --reuse-env-from preserves user/runtime settings but refreshes image
-tags from this package's .env.example so the upgraded service actually runs the
-new packaged runtime and monitor images. Use --keep-reused-image only when you
-intentionally want to keep the previous image tags.
+By default, --reuse-env-from creates the new .env from this package's
+.env.example first, then overlays existing user settings from the old .env.
+Image tags are intentionally kept from the new package so the upgraded service
+actually runs the new packaged runtime and monitor images. Use
+--keep-reused-image only when you intentionally want to keep previous image tags.
 USAGE
 }
 
@@ -38,42 +39,59 @@ while [[ $# -gt 0 ]]; do
   esac
 done
 
-if [[ -n "$REUSE_ENV_FROM" ]]; then
-  [[ -f "$REUSE_ENV_FROM" ]] || die "missing reuse env file: $REUSE_ENV_FROM"
-  if [[ ! -f "$ENV_FILE" ]]; then
-    cp "$REUSE_ENV_FROM" "$ENV_FILE"
-    log "copied existing env into new package: $REUSE_ENV_FROM -> $ENV_FILE"
-  else
-    log "keeping existing env at $ENV_FILE; reuse source ignored: $REUSE_ENV_FROM"
-  fi
-fi
+env_get_key() {
+  local env_path="$1"
+  local key="$2"
+  awk -F= -v key="$key" '$1 == key {sub(/^[^=]*=/, ""); print; exit}' "$env_path"
+}
 
-refresh_env_key_from_example() {
-  local key="$1"
-  local value
-  [[ -f "$ENV_EXAMPLE" ]] || die "missing $ENV_EXAMPLE"
-  value="$(awk -F= -v key="$key" '$1 == key {sub(/^[^=]*=/, ""); print; exit}' "$ENV_EXAMPLE")"
-  [[ -n "$value" ]] || return 0
-  if grep -q "^${key}=" "$ENV_FILE"; then
+env_set_key() {
+  local env_path="$1"
+  local key="$2"
+  local value="$3"
+  local tmp_env
+  if grep -q "^${key}=" "$env_path"; then
     tmp_env="$(mktemp)"
     awk -v key="$key" -v value="$value" '
       BEGIN { done=0 }
       $0 ~ "^" key "=" { print key "=" value; done=1; next }
       { print }
       END { if (!done) print key "=" value }
-    ' "$ENV_FILE" > "$tmp_env"
-    mv "$tmp_env" "$ENV_FILE"
+    ' "$env_path" > "$tmp_env"
+    mv "$tmp_env" "$env_path"
   else
-    printf '%s=%s\n' "$key" "$value" >> "$ENV_FILE"
+    printf '%s=%s\n' "$key" "$value" >> "$env_path"
   fi
-  log "refreshed $key from packaged .env.example"
 }
 
-if [[ "$UPDATE_PACKAGE_IMAGE" == "1" ]]; then
-  load_env
-  refresh_env_key_from_example "RPKI_IMAGE"
-  refresh_env_key_from_example "PROMETHEUS_IMAGE"
-  refresh_env_key_from_example "GRAFANA_IMAGE"
+overlay_reused_env() {
+  local source_env="$1"
+  local target_env="$2"
+  local key
+  local value
+  while IFS='=' read -r key _; do
+    [[ -n "$key" ]] || continue
+    [[ "$key" =~ ^[A-Za-z_][A-Za-z0-9_]*$ ]] || continue
+    case "$key" in
+      RPKI_IMAGE|PROMETHEUS_IMAGE|GRAFANA_IMAGE)
+        [[ "$UPDATE_PACKAGE_IMAGE" == "0" ]] || continue
+        ;;
+    esac
+    value="$(env_get_key "$source_env" "$key")"
+    env_set_key "$target_env" "$key" "$value"
+  done < <(grep -E '^[A-Za-z_][A-Za-z0-9_]*=' "$source_env" || true)
+}
+
+if [[ -n "$REUSE_ENV_FROM" ]]; then
+  [[ -f "$REUSE_ENV_FROM" ]] || die "missing reuse env file: $REUSE_ENV_FROM"
+  if [[ ! -f "$ENV_FILE" ]]; then
+    [[ -f "$ENV_EXAMPLE" ]] || die "missing $ENV_EXAMPLE"
+    cp "$ENV_EXAMPLE" "$ENV_FILE"
+    overlay_reused_env "$REUSE_ENV_FROM" "$ENV_FILE"
+    log "created new package env from .env.example and overlaid user settings from $REUSE_ENV_FROM"
+  else
+    log "keeping existing env at $ENV_FILE; reuse source ignored: $REUSE_ENV_FROM"
+  fi
 fi
 
 load_env
diff --git a/scripts/soak/run_soak.sh b/scripts/soak/run_soak.sh
index dff549f..ab0759d 100755
--- a/scripts/soak/run_soak.sh
+++ b/scripts/soak/run_soak.sh
@@ -416,10 +416,11 @@ max_existing_run_index() {
   local run_name
   local numeric_part
   shopt -s nullglob
-  for run_dir in "$RUNS_ROOT"/run_[0-9][0-9][0-9][0-9]; do
+  for run_dir in "$RUNS_ROOT"/run_*; do
     [[ -d "$run_dir" ]] || continue
     run_name="$(basename "$run_dir")"
     numeric_part="${run_name#run_}"
+    [[ "$numeric_part" =~ ^[0-9]+$ ]] || continue
     if (( 10#$numeric_part > max_index )); then
       max_index=$((10#$numeric_part))
     fi