Do nothing if we're debugging BIOS changes, unless forced

pack_stub

 #!/bin/sh
 # Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # All scripts should die on error unless commands are specifically excepted
 # by prefixing with '!' or surrounded by 'set +e' / 'set -e'.
 set -e
 # Clean up on regular or error exits.
 trap clean_temp EXIT
@@ skipping 90 matching lines @@
     exit $ret
     ;;
   --sb_extract)
     make_temp
     echo "The resources are extracted into: $TMP_DIR"
     untar_and_chdir "$SELF"
     # Don't remove the temporary folder on exit.
     TMP_DIR=""
     exit 0
     ;;
+  --force)
+    force_flag=1
+    ;;
   -h|"-?"|--help)
     echo "Shellball -- self-extract and install"
     echo ""
     echo "Usage: $SELF [options] [-- [inside-script-options]]"
     echo ""
     echo "options:"
     echo "           -h  show usage help"
     echo "           -V  show version of containing files"
     echo "   --sb_check  check content integrity"
     echo " --sb_extract  extract content to temp folder"
     echo ""
     echo " All other parameters will be passed to the script inside."
     echo ""
     echo " You can invoke as '$SELF -- -h'"
     echo " to see the usage and options of inside-script."
     echo ""
     exit 1
     ;;
   --debug | --verbose | -v)
     # do not shift here because this needs to be passed into the script
     IS_VERBOSE=1
     ;;
   --)
     shift
     ;;
 esac
 
+# Do nothing if we're debugging BIOS changes, unless forced
+if [ -e /root/.leave_firmware_alone ] && [ -z "${force_flag:-}" ]; then
+  echo "WARNING: $0 is disabled"
+  exit 0
+fi
+
 # Prepare execution environment
 make_temp
 allow_temp_exec
 untar_and_chdir "$SELF"
 if [ ! -x $SCRIPT ]; then
   error_exit "Cannot execute $SCRIPT"
 fi
 
 # Are we running in legacy mode or new flavor?
 PATH=".:$PATH"
@@ skipping 32 matching lines @@
   fi
 fi
 
 verbose_message "Run built-in script ($SCRIPT) ..."
 if ! $SCRIPT "$@"; then
   error_exit "ERROR: $SCRIPT failed."
 fi
 exit 0
 
 # Below are uuencoded blob. Don't put code behind exit 0.