Any hope for iMac that won't boot because of missing EFI file?

[NielsN]

First post here, a bit rambling but dont have all the facts at hand right now. Have an older Imac, FusionDrive, 21,5" with the glued screen, one morning waking it up from sleep I briefly got the desktop and email notifications, then it shut down. Starting up again it would not boot, it troes but progress bar stops at some point and it does not go any further. Did some searches and eventually got a message on screen saying something like "cannot boot because of missing EFI file". I have tried just about everything, safe mode, recovery mode, Internet recovery (computer does not have this I think) , resetting all kinds of things, no luck. Tried creating a bootable usb disk on my MBPPro but that does not help either. I can attach my Time Machine and get that up on the screen at startup as a choice, same as the bootable usb disk but it does not make a difference.
See some people have the same problem and I have not found anyone that managed to solve this.....
Took the machine to an authorized Apple repair facility in town and they did a check, said it probably was the motherboard but they refused to touch the machine since it was too old and obsolete....

 

[Yebubbleman]

I think Apple, somewhere, has a UEFI recovery drive image that you can download to make a recovery drive for Intel Macs that ought to work in this kind of situation. If you've tried it already, then I'd chalk that up to a failing logic board.

 

[NielsN]

Thank you for your feedback. I think when this happened, I recall seeing the email notification and then something about an Apple update, and then it shut down. I am not a wizard on computers, and find little on the net about UEFI, and what I find are for computers from 2011 when internet recovery and diagnostics were added. I think my computer is from late 2012, can check, but internet recovery does not work. When computer is turned on in safe mode I get up internet connection, can set that but when starting up the progress bar very slowly progresses, then stops anout 75% into the process. I can attach a Time Machine, choose that on startup and see everything on the Time Machine but I dont know what to do then, that does not help me.
If I find the UEFI file and put that on a memory stick, how do I get that into the computer when it will not start up?
The computer has High Sierra on it.

 

[Schnauzer World]

It sounds similar to the problem I had last month. Since you have another mac, you might try to reset/restore. Here are the videos which really helped me:

https://forums.macrumors.com/threads/2020-imac-boot-loop-problem.2436935/?post=33428635#post-33428635

 

[hobowankenobi]

Depending on the model, there may be a way to reset failed firmware. See if this applies to your Mac. If you can round up a second Mac...it could be worth a shot.

Oops...I see Schnauzer World beat me to it!

 

[Dimvol]

DFU and 2012? It needs EFI like a fish needs an umbrella. The system is erased and reinstalled. Old systems often cannot be installed via recovery due to unavailability on Apple servers. It is necessary to make an installation disk and install the system from it, and not via recovery. In the future, OCLP and a newer OS, for example, Ventura.
It does not have DFU. In 2012, it had not yet been invented.

 

[Nermal]

It sounds similar to the problem I had last month. Since you have another mac, you might try to reset/restore. Here are the videos which really helped me:

https://forums.macrumors.com/threads/2020-imac-boot-loop-problem.2436935/?post=33428635#post-33428635

The 2020 is really a different beast entirely. That fix is not going to work.

 

[Dimvol]

High Sierra and the EFI partition are not connected in any way. It presses the wrong buttons and instead of restoring it tries to run AHT (Apple hardware test). It was in EFI and is now missing. It is complaining about its absence. The recovery utility often cannot restore old systems, Apple deleted them or they are often unavailable. Therefore, the easiest way is to ask the owners for a ready-made bootloader (Open Core, OCLP) and install the system using the installation disk. But I would not install anything newer than Ventuа there - there are no hardware decoders. There is no point in restoring High Sierra itself - it is no longer possible to use it. It is outdated.

 

[Nguyen Duc Hieu]

First post here, a bit rambling but dont have all the facts at hand right now. Have an older Imac, FusionDrive, 21,5" with the glued screen, one morning waking it up from sleep I briefly got the desktop and email notifications, then it shut down. Starting up again it would not boot, it troes but progress bar stops at some point and it does not go any further. Did some searches and eventually got a message on screen saying something like "cannot boot because of missing EFI file". I have tried just about everything, safe mode, recovery mode, Internet recovery (computer does not have this I think) , resetting all kinds of things, no luck. Tried creating a bootable usb disk on my MBPPro but that does not help either. I can attach my Time Machine and get that up on the screen at startup as a choice, same as the bootable usb disk but it does not make a difference.
See some people have the same problem and I have not found anyone that managed to solve this.....
Took the machine to an authorized Apple repair facility in town and they did a check, said it probably was the motherboard but they refused to touch the machine since it was too old and obsolete....

Have you tried booting your iMac from an external storage device, like a working High Sierra external SSD, perhaps?
Booting from an external drive is expected to derive the machine from almost all issues existing in the internal SSD/HDD/Fusion drive.

 

[NielsN]

Thank you for answers, appreciate it.
I have an older MacbookPro that I installed a new Samsung 250HD in, one of the memory slots is no longer working because of bent pins so it runs on one 4 GB memory. (I think), works just fine for surfing etc but its getting tired.
About the Imac, I thought this machine could not be upgraded beyond High Sierra, this is also what I read when searching.
I made a bootable usb stick on the MBP, with High Sierra, but when trying to start the Imac with this the same thing happens, it starts up, can choose internet and choose the USB to boot from but the progress bar freezes again at 75% and nothing happens after that. I think I have lost the small usb external disk adapter I was using when installing the Samsung on the MBP, but Nguyen, what you are suggesting is to use this disk to try and boot the Imac? Can I try and boot the Imac from the MBP with just a usb cable? Never tried that....I am not so experienced in these matters. I have the old Time Machine and it also comes up as a start up option, can I use that maybe? Probably not.
It has now been quite a while since I was trying all kinds of start-up options but recovery does not work and this machine, I think does not have internet recovery.

 

[Nguyen Duc Hieu]

1. iMac 2012 or later can do Internet Recovery.
2. You can install Mac OS on an external SSD and run Mac OS from there.
Process:
1. Create a USB installer of Mac OS (iMac 2012 can go with Mojave I guess)
2. Plug the USB installer into your iMac.
3. Plug an external SSD into your iMac. Blank SSD
4. Power the iMac and choose to boot from the USB installer.
5. Open Disk Utility and format the external SSD
6. Install Mac OS to the external SSD.
7. Reboot the iMac from the external SSD.

 

[NielsN]

Only one problem here, I created a bootable usb stick with High Sierra on the MBP and tried to boot from that on the Imac but same result as booting Imac before, progress bar stops at 50% or 75% depending on start up mode and it will stay there, nothing more is happening.

 

[Nguyen Duc Hieu]

Only one problem here, I created a bootable usb stick with High Sierra on the MBP and tried to boot from that on the Imac but same result as booting Imac before, progress bar stops at 50% or 75% depending on start up mode and it will stay there, nothing more is happening.

Similar symptom as my iMac 2009 when its GPU was faulty. After replacing the GPU, the issue went away. (nothing changed except the GPU)