Late 2012 Mac Mini EFI Firmware Update 1.8 (to fix USB problems after wake):
Info from the download page. (Should also appear in software update for supported Mini/OS versions.)
"Mac mini EFI Firmware Update v1.8
This update is recommended for Mac mini (late 2012) models. This update addresses an issue that may prevent a USB keyboard from being recognized after the system wakes from sleep.
File Size: 4.8 MB
System Requirements: OS X v10.8.5, v10.9.5 or v10.10.4 and later
"
Again not seeing the download icon/link on the web page but found a D/L link from the us page. (Here's how to verify authenticity of downloaded Apple updates.)
Added a FYI/link to the earlier page on this problem. Used the D/L to update a 2012 Mini with previous bootrom MM61.0106.B08 from the 2015-001 EFI Security Update. New Bootrom version after EFI Update 1.8 is MM61.0106.B09.
I later saw several owners that had problems with .B08 say this update seems to have helped. However a thread in the apple mac mini forum had 2 posts from owners that had an update failure (both used software update) with the mini only showing a blinking LED on power-on.
Also some posts that the update would not apply. (Appeared in software update, installed, bootrom version not updated, appears again in SU.) Check drive format, as apple notes Firmware updates for Intel-based Macs require a GUID partition scheme. (When the firmware update prompts to restart the mac, on reboot you should see a progress bar fill in as part of the flash update process.)
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