The Apple SMC contains security critical code. This is a utility designed for the iteraction with the System Management Controller and it's updates.

apple, arm, efi, firmware, smc, utility
gem install smcutil -v 0.1.6


smcutil for Appple SMC

smcutil is a command line tool for reading Apple's SMC payloads, validating them, fingerprinting them and extracting the contents for disassembly.


Currently looking for a number of MacBooks with good SMCs that may be offered as tribute for save and waiting on Stellaris development hardware. Anyone have a sub-micron wealder out there?


Install it yourself as:

$ gem install smcutil


$ smcutil
Usage: smcutil {command} [PARAMS]
Command is one of:
  validate {file.smc}:
    Causes smcutil to parse the Apple SMC file and validate correctness.
  info {file.smc}:
    Prints information about the SMC update file.
  decode {file.smc} {output.bin}:
    Pretends to execute an update of the SMC flash as though the output.bin file is the SMC flash ROM.
  shred {file.smc} {output_dir}:
    Pulls apart each flash region, so that multiple passes can be examined
  save {output.bin}:
    Has magical bear powers.  Loads SMC update payload to capture the contents of the application partition.
    No warrently, may bork hardware.


After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to


Bug reports and pull requests are welcome on GitHub at This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.


The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the SmcUtil project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.