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Booting your Mac OS X in safe mode with NVRAM modifications

Some times we might require our mac to be booted into safe mode to fix/resolve some issues. Your mac can be booted into safe mode in two ways

  1. Hold "Shift" key on your mac keyboard to boot your mac into safe mode.
  2. If you can not boot with your keyboard(in case your keyboard is not recognized or some problem)  then you can perform below operations :
    1. Establish a remote connection such as SSH to the mac.
    2. Run in terminal " sudo nvram boot-args="-x", press enter/return. ( You can also add "-x -v" for verbose mode booting of safe mode)
    3. To reset back to normal mode run "sudo nvram boot-args=" " (without any arguments).

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Way 1 :
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On the right side panel Under hardware overview section, we can see Boot ROM Version and SMC (Firmware) Version.

Way 2 :
Run the below command in terminal to get boot ROM version and SMC(firmware) version :
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On Macs running Mountain Lion, Mavericks  and Yosemite:
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sudo kextunload -b
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On Mac running El Capitan:
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