How to update your firmware, reset the SMC, and reset the NVRAM (or zap the PRAM), and what they do. Updated for High Sierra.
Additional info about how you can install and upgrade to High Sierra, its new Content Caching feature, how it changes firmware updates, changes to NVRAM, and more.
Safe mode, or Recovery? Which type of Recovery? How to engage all those useful modes at startup, and when shutting down.
How to enable or mute your Mac’s startup chime, and other neat tricks of the NVRAM.
These store key information for your Mac. Resetting the SMC and NVRAM is no panacea, but can transform an apparently dying Mac.
All the useful key combinations, arranged by function rather than keys.
SIP protects your Mac from rogue KEXTs too, and prevents tools from attaching to protected processes.
What to do when your Mac won’t start up, and is acting dead, or at least mortally wounded.
After an interrupted firmware update, my iMac refuses to start up. What can I do?