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Need EFI for iMac 13,1 EMC2546 A1419 i7
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5 years 10 months ago #10005 by wallybear
Need EFI for iMac 13,1 EMC2546 A1419 i7 was created by wallybear
Hi,
I'm trying to revive an iMac 27" (EMC2546) that got its EFI corrupted by Clover bootloader, with no success.
The symptom is a boot loop: iMac makes startup sound, display white, restarts, new boot sound, screen white, and so on.
I successfully saved its EFI using raspberry + flashrom.
I downloaded the right EFI in the download section, reflashed it but it doesn't work; I tried each of the following steps:
-modifying serial number with the iMac right one
-no modifications at all
-cleaning ME region
-copying ME from original efi
-reflash original efi with ME region cleaned
Nothing of the above can get me to booting iMac; the downloaded efi doesn't even try to boot (no sound, third diagnostic LED doesn't light up, after a while the fan maxxes), when I reflash the original efi it goes back to boot sound/screen white/loop
Is it possible the efi in your repository is bad? I didn't found any other efi in the whole internet.
Any help? I'm out of ideas
Could you please give me another EFI dump to try or is there some other efi source to try?
If someone thinks he can fix my original EFI dump I can post it here.
Thanks a lot.
I'm trying to revive an iMac 27" (EMC2546) that got its EFI corrupted by Clover bootloader, with no success.
The symptom is a boot loop: iMac makes startup sound, display white, restarts, new boot sound, screen white, and so on.
I successfully saved its EFI using raspberry + flashrom.
I downloaded the right EFI in the download section, reflashed it but it doesn't work; I tried each of the following steps:
-modifying serial number with the iMac right one
-no modifications at all
-cleaning ME region
-copying ME from original efi
-reflash original efi with ME region cleaned
Nothing of the above can get me to booting iMac; the downloaded efi doesn't even try to boot (no sound, third diagnostic LED doesn't light up, after a while the fan maxxes), when I reflash the original efi it goes back to boot sound/screen white/loop
Is it possible the efi in your repository is bad? I didn't found any other efi in the whole internet.
Any help? I'm out of ideas
Could you please give me another EFI dump to try or is there some other efi source to try?
If someone thinks he can fix my original EFI dump I can post it here.
Thanks a lot.
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5 years 9 months ago #10102 by wallybear
Replied by wallybear on topic Need EFI for iMac 13,1 EMC2546 A1419 i7
Doesn't matter anymore, I succeeded by myself this night. I re-edited the EFI available in downloads using UEFI Tool to replace the ME section (taken from my original EFI) and this time it re-assembled correctly, as reflashing it on the Mac revived it. 
Hooray!
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5 years 9 months ago #10114 by wallybear
Replied by wallybear on topic Need EFI for iMac 13,1 EMC2546 A1419 i7
I just noticed a strange glitch... The iMac is working fine, but it cannot recognize more than two RAM modules. It knows that 4 slots are present, but doesn't matter which modules I install (size/number/position), it will always view 2 modules. 
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5 years 9 months ago #10151 by wallybear
Replied by wallybear on topic Need EFI for iMac 13,1 EMC2546 A1419 i7
Solved! After applying latest firmware update the iMac recognizes all 4 slots. I presume that the firmware I flashed was for a 21.5" model, that has only 2 memory slot. Finally an happy end...
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