Issue:
When attempting to install the EFI Firmware Update for MacBook Pro, the update would attempt to install but fail with the message:
An error has occurred
The digital signature on MacBook Pro EFI Firmware Update is missing or is invalid. The update may have been tampered with since being signed by Apple. Click Update to download and check the update again. (203)
Resolution:
- Renamed the update folder – Found /Library/Updates
- Manually downloaded update from Apple support pages and install.
- Re-run AppStore updates to ensure that the update disappears from the updates to be applied.