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#MACBOOK PRO 3 BEEPS AFTER RUNNING INFINITE LOOP UPDATE#
#MACBOOK PRO 3 BEEPS AFTER RUNNING INFINITE LOOP FULL#

If it does not, you can try resetting its SMC and NVRAM, as described here. Once complete, the Mac will restart normally and should function correctly again. Once a recent model has sounded the tones indicating it has entered EFI ROM recovery, a progress bar should be displayed, during which recovery will take place automatically.

old models, prior to about 2008-10, may need to be started up from a Firmware Restoration CD to restore the EFI ROM.

MacBook Pro 2016 models will not make any tones, but should also automatically recover the EFI ROM,.

more recent models should automatically recover the EFI ROM after sounding the - … - tone,.

If something goes wrong with an EFI ROM update, or the Mac loses power during the update, the Mac can be left with corrupt firmware, and may refuse to start up properly.

#MACBOOK PRO 3 BEEPS AFTER RUNNING INFINITE LOOP FULL#

These are usually listed in the Installations item in System Information, which will also give full details of the installed version.

#MACBOOK PRO 3 BEEPS AFTER RUNNING INFINITE LOOP UPDATE#

All models which are upgraded to run High Sierra receive a firmware update as part of that installation. Spontaneous corruption suggests that something even more serious is going on, and needs full hardware diagnostics.ĮFI ROM updates only occur now as part of a macOS update. The great majority of problems with EFI ROM corruption occur when an EFI update is interrupted. Much older PowerPC and Classic Macs are different again, and some flash the display rather than making error tones. one long tone when you hold the power button – EFI ROM update is in progress (Macs before 2012).three long, three short, and three long tones (the inverse of Morse SOS) – EFI ROM is corrupt and is being recovered.three tones followed by a 5 second pause, repeating – installed RAM has failed initial testing.a single tone repeated every 5 seconds – no RAM has been detected.normal startup chime – memory and ROM appear good, normal startup will continue.On Intel-based models prior to the MacBook Pro 2016, the following sounds are possible: Until October 2016, Macs made sounds when starting up, to indicate their health or serious problems.