To brick is the English colloquial expression for the fact that your Mac becomes a brick because it gets unusable. Apparently in some cases this is exactly what happens with the Catalina update.
The update to Catalina also brings an EFI update for many computers, which is flashed on the corresponding chip on the logic board, and this seems to go partially wrong. This is expressed in the fact that the computers don’t start anymore and – even worse – don’t accept any keystrokes anymore. So you can’t just boot from an external data medium. The Mac is unusable in this state.
A call to Apple always seems to lead to the same answer: the logic board is defective on hardware level, the exchange costs between $400 and $700. That this defect is related to the update seems to be confirmed more and more. We can therefore only advise against upgrading to Catalina currently, also because of the current Apple Mail problems.
Wait with the update to Catalina on older computers.
Users report in the official Apple forums mainly about Macs from 2015 and older that were bricked during the update. Affected are MacBook Pro 2015, MacBook Pro 2012, iMac, MacBook Air, Mac mini. However, the problem does not seem to come as a surprise because testers already reported damaged devices in the beta phase.
If you are affected by this problem we advise you not to pay for a logicboard exchange. Either wait until Apple admits a connection to the Catalina Update or look for a free repair shop that can flash or exchange EFI chips. This is quite possible (don’t let Apple scare you) and costs a fraction of a new board.
