diff --git a/bootstrap.sh b/bootstrap.sh
index 71006b9..8eefca0 100644
--- a/bootstrap.sh
+++ b/bootstrap.sh
@@ -26,23 +26,23 @@
 # variable set.
 # TODO(mohrr) find out a way to do this without PW_CHECKOUT_ROOT.
 if test -n "$PW_CHECKOUT_ROOT"; then
-  _BOOTSTRAP_PATH="$(_bootstrap_abspath "$PW_CHECKOUT_ROOT/bootstrap.sh")"
+  _PW_BOOTSTRAP_PATH="$(_bootstrap_abspath "$PW_CHECKOUT_ROOT/bootstrap.sh")"
   # Downstream projects need to set PW_CHECKOUT_ROOT to point to Pigweed if
   # they're using Pigweed's CI/CQ system.
   unset PW_CHECKOUT_ROOT
 # Shell: bash.
 elif test -n "$BASH"; then
-  _BOOTSTRAP_PATH="$(_bootstrap_abspath "$BASH_SOURCE")"
+  _PW_BOOTSTRAP_PATH="$(_bootstrap_abspath "$BASH_SOURCE")"
 # Shell: zsh.
 elif test -n "$ZSH_NAME"; then
-  _BOOTSTRAP_PATH="$(_bootstrap_abspath "${(%):-%N}")"
+  _PW_BOOTSTRAP_PATH="$(_bootstrap_abspath "${(%):-%N}")"
 # Shell: dash.
 elif test ${0##*/} = dash; then
-  _BOOTSTRAP_PATH="$(_bootstrap_abspath \
+  _PW_BOOTSTRAP_PATH="$(_bootstrap_abspath \
     "$(lsof -p $$ -Fn0 | tail -1 | sed 's#^[^/]*##;')")"
 # If everything else fails, try $0. It could work.
 else
-  _BOOTSTRAP_PATH="$(_bootstrap_abspath "$0")"
+  _PW_BOOTSTRAP_PATH="$(_bootstrap_abspath "$0")"
 fi
 
 # Check if this file is being executed or sourced.
@@ -66,7 +66,7 @@
 # Downstream projects need to set something other than PW_ROOT here, like
 # YOUR_PROJECT_ROOT. Please also set PW_ROOT before invoking pw_bootstrap or
 # pw_activate.
-PW_ROOT="$(dirname "$_BOOTSTRAP_PATH")"
+PW_ROOT="$(dirname "$_PW_BOOTSTRAP_PATH")"
 export PW_ROOT
 
 # Please also set PW_PROJECT_ROOT to YOUR_PROJECT_ROOT.
@@ -76,7 +76,7 @@
 . "$PW_ROOT/pw_env_setup/util.sh"
 
 pw_deactivate
-pw_eval_sourced "$_pw_sourced"
+pw_eval_sourced "$_pw_sourced" "$_PW_BOOTSTRAP_PATH"
 pw_check_root "$PW_ROOT"
 _PW_ACTUAL_ENVIRONMENT_ROOT="$(pw_get_env_root)"
 export _PW_ACTUAL_ENVIRONMENT_ROOT
@@ -86,7 +86,7 @@
 # an ASCII art banner here.
 
 # Run full bootstrap when invoked as bootstrap, or env file is missing/empty.
-if [ "$(basename "$_BOOTSTRAP_PATH")" = "bootstrap.sh" ] || \
+if [ "$(basename "$_PW_BOOTSTRAP_PATH")" = "bootstrap.sh" ] || \
   [ ! -f "$SETUP_SH" ] || \
   [ ! -s "$SETUP_SH" ]; then
   pw_bootstrap --shell-file "$SETUP_SH" --install-dir "$_PW_ACTUAL_ENVIRONMENT_ROOT" --json-file "$_PW_ACTUAL_ENVIRONMENT_ROOT/actions.json" --config-file "$PW_ROOT/pw_env_setup/config.json"
@@ -97,7 +97,7 @@
 fi
 
 unset _pw_sourced
-unset _BOOTSTRAP_PATH
+unset _PW_BOOTSTRAP_PATH
 unset SETUP_SH
 unset _bootstrap_abspath
 
diff --git a/pw_env_setup/util.sh b/pw_env_setup/util.sh
index 2a6b584..348730c 100644
--- a/pw_env_setup/util.sh
+++ b/pw_env_setup/util.sh
@@ -73,7 +73,13 @@
 
 pw_eval_sourced() {
   if [ "$1" -eq 0 ]; then
-    _PW_NAME=$(basename "$_BOOTSTRAP_PATH" .sh)
+    # TODO(pwbug/354) Remove conditional after all downstream projects have
+    # changed to passing in second argument.
+    if [ -n "$2" ]; then
+      _PW_NAME=$(basename "$2" .sh)
+    else
+      _PW_NAME=$(basename "$_BOOTSTRAP_PATH" .sh)
+    fi
     pw_bold_red "Error: Attempting to $_PW_NAME in a subshell"
     pw_red "  Since $_PW_NAME.sh modifies your shell's environment variables,"
     pw_red "  it must be sourced rather than executed. In particular, "