The package_patch command accepts two archives (a base/release and a patch) produced by flutter build (only aabs are currently supported) and creates patch artifacts for every architecture contained in both archives.

This command accepts the following arguments:

archive-type: The type of the archives to process. Currently, only aab is supported.
release: The path to the base/release archive.
patch: The path to the patch archive.
patch-executable: The path to the patch executable.
output: The path to the directory where the patch artifacts will be created.

Sample usage:

dart run updater_tools package_patch \
  --archive-type=aab \
  --release=release.aab \
  --patch=patch.aab \
  --patch-executable=path/to/patch \
  --output=patch_output

If release.aab contains the default architectures produced by flutter build (arm64-v8a, armeabi-v7a, and x86_64), this will produce the following in the patch_output directory:

patch_output/
  ├── arm64-v8a.zip
  │   ├── dlc.vmcode
  │   └── hash
  ├── armeabi-v7a.zip
  │   ├── dlc.vmcode
  │   └── hash
  └── x86_64.zip
      ├── dlc.vmcode
      └── hash

In each .zip:

dlc.vmcode: the bidiff file produced by the patch executable
hash: the sha256 digest of the fully constituted (aka pre-diff) patch file (libapp.so on Android).