Trapped: MacBook always shuts down during EFI SMC Update 1.8. Can't boot. How to remove updater from boot routine? MacBook Pro i7 Mid-2012 (MacBookPro9,2) running Mac OS X 10.8.5: Downloaded the "offered" EFI SMC Update 1.8 through the AppStore Updates. MacBook restarted, grey progress bar appears w/ spinning wheel, progress bar disappears at 20%, wheel spins a few more seconds, then display turns black and Mac shuts down.

When I hit the power switch, same routine again: progress bar &amp; spinning wheel until Mac shuts down w/ incomplete update. Tried SMC reset and Parameter RAM reset. Nothing helps. Can boot from recovery partition, but otherwise I'm suddenly trapped, which really sucks.

Don't know what to do next. My idea would be to boot in Single User Mode (CMD-S at restart) and remove the SMC EFI Updater from the boot routine via command line. The question is: How?
EFI firmware updates are 'staged' in the normally hidden EFI partition on your disk, which typically resides at device /dev/disk0s1.

Once in single-user mode, you can create a folder in which to mount this partition, then mount it like so:

mkdir /Volumes/efi
mount -t msdos /dev/disk0s1 /Volumes/efi


From here, navigate into the /EFI/APPLE/FIRMWARE/ sub-folder of the EFI partition.

If you find some files here, probably these are what your MacBook is trying to process and getting stuck on. You can safely delete them and reboot.