File picker, Dynamic Island and media controls

Fix a sideloaded app whose file picker does nothing, or that never shows in the Dynamic Island or opens from media controls.

Some system features only work when the app's bundle ID matches the App ID its provisioning profile was made for. Signers keep the app's original bundle ID by default, so the app installs and runs, but iOS leaves these features off.

Symptoms

The file picker opens empty, does nothing, or cannot import a file.
Playback never shows in the Dynamic Island.
Tapping the media controls does not open the app.

Fix: sign with the profile's App ID

Find the App ID. Open the certificate checker, add your .mobileprovision and read App ID.
In Feather instead: Settings > Certificates, hold the certificate, then Get Info > View Entitlements. Copy the value of application-identifier and drop everything up to and including the first dot. ABCDE12345.app.example.files becomes app.example.files.
Sign the app again, replacing its bundle ID with that value.
Install it.

If the App ID is *, the profile accepts any bundle ID and this fix does not apply.

Trade-offs

Trade-off	What to do
One App ID per profile: a second app signed with it replaces the first	Use it for the app where these features matter most
The new bundle ID installs as a separate app, without the old copy's data	Export the data first. See bundle identifiers and updates
Push notifications tied to the original bundle ID stop	Keep the original bundle ID for apps that need push
Updates only install over it when signed with the same App ID	Note the App ID and reuse it for every update

Sources

Apple Developer: CFBundleIdentifier
Feather: project page

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