MacRumors has corralled multiple reports of the macOS 12.3 Monterey update bricking Macs that have had their logic boards replaced, specifically 14- and 16-inch MacBook Pro models. The problem appears to be related to a firmware bug that causes these Macs to enter an endless reboot loop or an “iBoot Panic” message. For luckier users, the update completes, but the Mac remains on an earlier version of macOS. For now, avoid updating your Mac if Apple has replaced its logic board as part of a repair. Apple is aware of the problem, and a fix will likely appear soon. Due to Apple integrating more hardware components onto the logic board, including memory and storage, replacements have become an increasingly common way to fix a wide variety of problems.