astrid dot tech

Caligula Burning ROM

dd for the lazy

March 2023 - March 2023

rust Linux macos nixos ffi


A screenshot of Caligula working.

Caligula is a tool for burning ROMs to drives. It was made as a replacement for dd and Balena Etcher, and was borne out of frustrations with both.

This is a non-exhaustive feature list:

  • pretty graphs
  • removable USB device detection
  • compressed inputs
  • SHA-verification of inputs
  • automatically running su, sudo, or doas for you
  • post-write disk verification

Supported systems:

  • /(aarch64|x86_64)-(darwin|linux)/


My frustrations with dd:

  • Being unixware, it is comically minimal as usual
  • It won’t detect removable USB devices for you
  • You need to remember type in the same string of flags
  • Lack of good progress indicators on all systems (no, status=progress is not good enough and it’s also Linux-only)
  • No builtin SHA verification
  • No post-write correctness verification

My frustrations with Etcher:

  • It’s a 100MB electron blob
  • It spies on you
  • It’s not a terminal app
  • Seriously why do you need a web browser to write bytes to a disk
  • For how often compressed ISOs are distributed, it’s kinda shameful that

My frustrations with both:

  • No pretty graphs
  • NIH syndrome


The bulk of the project was completed in 9 days, during weekends, nights, and lunch breaks. This got the project to a state where I could release it, with features like:

  • the Wizard
  • removable USB device detection
  • pretty graphs
  • compressed inputs
  • disk verification

There are features occasionally added, when I have the time and motivation to add them.


It’s the first repo I’ve made that got over 100 stars on Github. Supposedly people use it.