Encounter errors like KeySystem link failure or Delta session mismatch? Here’s how to fix them.
| Error Message | Likely Cause | Solution |
|---|---|---|
| DRM_ERROR_SESSION_NOT_OPENED | The link was never established or was prematurely closed. | Reinitialize MediaDrm and ensure openSession() succeeds. |
| ERROR_DRM_CANNOT_HANDLE | The KeySystem doesn’t support delta updates. | Check license server capabilities; fall back to full license request. |
| Attestation failed: delta mismatch | The TEE’s key derivation counter is out of sync (often after a factory reset without proper keybox). | Requires OEM keybox re-provisioning. Only fixable by vendor. |
| L1 fallback to L3 | The link’s root of trust is broken (custom kernel, rooted device). | Restore stock boot image or use Magisk Hide + Universal SafetyNet Fix. | delta android keysystem link
The plugin calls into the TEE via a secure monitor call (SMC). This creates the link: a unique session ID tied to the current application process. The TEE responds with an attestation certificate signed with a device-specific private key that never leaves the TEE. Encounter errors like KeySystem link failure or Delta
Why does this link matter? Without it, secure streaming would be impossible. | | Attestation failed: delta mismatch | The