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macrumors bot
Original poster
Apr 12, 2001

Apple has released an update for late 2012 iMac models that fixes issues related to sleep and Thunderbolt, as well as compatibility when using 5GHz Wi-Fi frequencies. The update is recommended for all "late 2012" iMacs.

iMac EFI Update 2.0 can be downloaded from Apple's support site or through the Mac App Store on affected iMacs.
About iMac EFI Update 2.0

This update is recommended for all iMac (late 2012) models. This update contains general performance fixes pertaining to sleep and Thunderbolt, and improves compatibility when using the 5GHz band in Wi-Fi.

Boot ROM or SMC Version Information: After Update is complete:

Build version: 010A.05
ROM version: IM131.88Z.010A.B05.1211151146
It's not clear if this is in addition to the Wi-Fi Update released earlier today, or if it includes that fix as well as a few more iMac-specific ones.

Update: Apple has released a similar MacBook Pro Retina EFI Update v1.1 for the 13-inch Retina MacBook Pro.

Article Link: Apple Releases iMac EFI Update 2.0 to Fix Sleep and Thunderbolt Issues
Last edited:


macrumors 6502a
Oct 19, 2007
Both updates (the WiFi update *and* the EFI update) came through on my brand new 21" iMac. Must be distinct.

Chupa Chupa

macrumors G5
Jul 16, 2002
I wonder if this fixes the unmount on sleep w/ USB 3 hard drives. Otherwise what other sleep issues is the new iMac having? (Not home to try right now). Curious b/c the USB 3 issue was the only one I experienced. I wish Apple was more detailed in their update synopsis.


macrumors 68020
Jul 22, 2002
Good to see they are on top of things, just wondering how many updates will be waiting for new iMac users when we get them?


macrumors 68040
Jan 28, 2009
Will this help my 21.5" late 2012 iMac? I have issues waking from sleep whereby it wakes to a white screen only.


macrumors newbie
Jun 12, 2012
and mine (5 day old iMac) says this software is not supported on my system for both upgrades. Weird.


macrumors member
May 6, 2003
Maine, USA
I posted this in another thread last night - I spent some time on the phone last night with Apple support after both of yesterday's updates failed on my 27", 2012 iMac. They were surprised at the updates not working for me and confirming that, yes, as best they could tell the updates should work on both the 21" and 27" iMacs. They downloaded info from my machine to forward on to engineering and we're scheduled to talk again on Wednesday to see what they've found out about this problem. I told them that there were others besides me experiencing this issue.

Any rhyme or reason we can figure out here? Anyone with a 27 incher that had either or both of today's updates work? I'm seeing posts where the updates worked on 21" machines, and failures on 27" machines.

UPDATE: looks like they've changed the download page here:
to specify that the EFI update is for the 21.5" iMac only.

The WiFi update still says it is for all late 2012 Macs, but does not run on my 27"


macrumors regular
Mar 27, 2012
By the time I get mine I feel like they will have everything fixed lol

Exactly.....hope that apple is holding on to all the orders to the resellers until things have been resolved.

Still waiting for the 21.5" fully loaded since Dec 15


macrumors newbie
Jan 2, 2013
Both updates said not for my system. I have a 27" 2012 iMac that just arrived today.
My 27" is a week-old and I have shut off sleep mode as it has a problem waking and requires my password and all open programs are quit. I guess our up will follow...
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