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iMac 17,1 (Retina 5K, 27-inch, Late 2015) EFI firmware update failures
- Thread starter zorinlynx
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Wow- can’t believe this is still going on. Check out how I got mine to update in post #10 of this thread.
That’s great! So you simply replaced the Apple SSD with a fresh NVMe blade, installed there directly and the bootrom update worked?
Replacing the Apple SSD with a Samsung (or other) branded stick is quite complicated as you can see in this video:
You also need an adapter for the SSD because Apple used a custom pin layout for the SSD socket. I also read somewhere that some adapters work rather poorly and cause hard to diagnose problems.
As long as there are no compatibility problems with recent macOS releases it would not be worth it for me.
You also need an adapter for the SSD because Apple used a custom pin layout for the SSD socket. I also read somewhere that some adapters work rather poorly and cause hard to diagnose problems.
As long as there are no compatibility problems with recent macOS releases it would not be worth it for me.
I never tried it because I could not find a reasonably priced used thunderbolt 2 to sata adapter where I live.
Booting from USB hard drives does not do anything. Tried it multiple times with different macOS versions.
I know this, I have updated 27” iMacs many times with NVMe SSDs in the past, so this is known territory for me.
But the bootrom issues of the Late 2015 iMacs are new information for me, thus I wanted to know sufficient before I start the next project.
Thanks,
Magnus
Most of the success stories (including mine) involve installing a SATA disk and putting the new OS on it. The firmware updates and after that you are fine going back to the blade.
SAME PROBLEM WITH IMAC15,1 and EFI 235.0.0.0.0
I have an iMac 27" Retina 5K (late 2014), i7-4Ghz, 3TB Fusion Drive.
This machine has (now had) a 128GB Apple PCIe-SSD from SanDisk.
Stuck at EFI 235.0.0.0.0 after any upgrade from High Sierra.
I did:
Clean installation of Mojave, Catalina and BigSur on newly constructed fusion drive.
Clean installation of Mojave, Catalina and BigSur with "destroyed" fusion drive only on SSD.
Clean installation of Catalina with "destroyed" fusion drive only on HD. While HD is problematic (3% of blocks with access time over 500ms, but no bad blocks) no more tests.
Clean installation of Mojave, Catalina and BigSur with "destroyed" fusion drive and on external Thunderbolt PCIe (Transcend Jetdrive).
All of this didn't touch the old firmware at all and it stayed at 235.0.0.0.0.
I then removed the defective HD and the SSD and installed on an SATA-SSD: Firmware update to 432.60.3.0.0.
After that I installed an PCIe SSD.
And yes: It would have been interesting to know if it would have worked to just put in the new SSD and install it on this to get the firmware-update...
As said above, Apple SSD ist SanDisk, type 128GB SDNEP 655-1837F.
I have an iMac 27" Retina 5K (late 2014), i7-4Ghz, 3TB Fusion Drive.
This machine has (now had) a 128GB Apple PCIe-SSD from SanDisk.
Stuck at EFI 235.0.0.0.0 after any upgrade from High Sierra.
I did:
Clean installation of Mojave, Catalina and BigSur on newly constructed fusion drive.
Clean installation of Mojave, Catalina and BigSur with "destroyed" fusion drive only on SSD.
Clean installation of Catalina with "destroyed" fusion drive only on HD. While HD is problematic (3% of blocks with access time over 500ms, but no bad blocks) no more tests.
Clean installation of Mojave, Catalina and BigSur with "destroyed" fusion drive and on external Thunderbolt PCIe (Transcend Jetdrive).
All of this didn't touch the old firmware at all and it stayed at 235.0.0.0.0.
I then removed the defective HD and the SSD and installed on an SATA-SSD: Firmware update to 432.60.3.0.0.
After that I installed an PCIe SSD.
And yes: It would have been interesting to know if it would have worked to just put in the new SSD and install it on this to get the firmware-update...
As said above, Apple SSD ist SanDisk, type 128GB SDNEP 655-1837F.
From what have been said earlier in this thread and others, I'd say that it has to be an install made on a SATA device (HDD or SSD) while no other storage device is present in the system. That seem to kick in the FW update if it has gotten stuck.
WARNING TO ALL WITH THIS MODEL.
Count your lucky stars that your firmware has not updated properly because on one of my 2 x Late 2015 i7 4.0gHz iMacs, I updated to Monterey and the firmware did successfully update with no extra effort required.....BUUUT...
I can go into further detail, but in a nutshell, the very newest firmware supplied with Monterey IM171.88Z.F000.B00.2203161718 [Last numbers in EFI equating to 16th March 2022](451.120.7.0.0) has significantly reduced the performance of the machine. I have tried swapping EVERYTHING, 1 at a time, between the good machine to the bad. And it all leads to the logic board and the firmware which is now irrevocably flashed to it.
For reference, my good machine is running an earlier version of Catalina 15.7 from Feb 2021 from an "Install MacOS Catalina" bootable image I luckily saved (no longer available from Apple officially) before realising the next update of Catalina also had some ridiculous issues, so I managed to revert to what I'd consider the last, golden update for this model. And the EFI firmware/BOOT ROM version is showing as IM171.88Z.F000.B00.2102262339 (429.100.7.0.0). Last number in EFI equating to 26th Feb 2021.
Honestly, after monitoring and logging via iStat and Stats, the differences are HUGE. It seems as if they've fully abandoned support for the firmware and just done their usual subtle planned obsolescence, this time by deploying a final(?) half-assed firmware update.
It seems to create a bottleneck in the whole system by limiting the full interfacing of the pcie/nvme SSD, whether that be a lane bandwidth issue or an internal SSD caching issue, in OEM (AND) 3rd party blade SSDs!
As I say, I can provide data as proof but just take my word for it. I've also tried around 8 different SSDs, varying from the original SSD that came in it from factory, to OWC X2 who claim guarantee to work, to most Samsung aftermarket models(970,980,970evo,970evo plus, 980 pro), WD blacks, blues, you name it. Most let you install the OS and will migrate the data fine. And will tend to appear to work pretty slick on basic tasks like browsing, videos, etc. But as soon as you try to do some CPU intensive tasks, like stream via OBS, it just gets completely overwhelmed and majorly struggles to multitask.
The weird part is that using BlackMagic Disk Speed test on all of the 3rd party SSDs yields great results! Circa 2500Mb/s read/write on average, some 3000+. But it just doesn't perform well at all in practice.
Tried all types of RAM, OEM, OWC, bla bla...all possible versions of macOS, fresh installs, time machine restores....but firmware just cannot go backwards..
Tried swapping peripherals, USB hubs, nothing plugged in....all the same outcome.
Compare that to my other machine of exact same spec, running a Samsung 970 EVO Plus 1TB, and it can run multiple processes at once without breaking a sweat. OBS, Ableton, Logic Pro,5 separate web browsers....
E.g. OBS runs at around 6-12% CPU, even with other tasks running, on a high load scene on my good iMac while streaming AND recording.
The bad iMac board runs at around 60+% CPU load with OBS open alone! Which spikes up and down hitting 100% load frequently!
I think I have tried everything I can think of anyway, open to more suggestions, but I bet I've tried it.
In the meantime, I await arrival of another machine of same spec I've sourced which the owner confirmed is stuck at the fabled 170.00.... even though he updated to Monterey, so fingers crossed!
So in conclusion, I'd personally be thankful if my iMac 27 inch 5K Late 2015 firmware is not in fact updating fully!! If it ain't broke.......
Count your lucky stars that your firmware has not updated properly because on one of my 2 x Late 2015 i7 4.0gHz iMacs, I updated to Monterey and the firmware did successfully update with no extra effort required.....BUUUT...
I can go into further detail, but in a nutshell, the very newest firmware supplied with Monterey IM171.88Z.F000.B00.2203161718 [Last numbers in EFI equating to 16th March 2022](451.120.7.0.0) has significantly reduced the performance of the machine. I have tried swapping EVERYTHING, 1 at a time, between the good machine to the bad. And it all leads to the logic board and the firmware which is now irrevocably flashed to it.
For reference, my good machine is running an earlier version of Catalina 15.7 from Feb 2021 from an "Install MacOS Catalina" bootable image I luckily saved (no longer available from Apple officially) before realising the next update of Catalina also had some ridiculous issues, so I managed to revert to what I'd consider the last, golden update for this model. And the EFI firmware/BOOT ROM version is showing as IM171.88Z.F000.B00.2102262339 (429.100.7.0.0). Last number in EFI equating to 26th Feb 2021.
Honestly, after monitoring and logging via iStat and Stats, the differences are HUGE. It seems as if they've fully abandoned support for the firmware and just done their usual subtle planned obsolescence, this time by deploying a final(?) half-assed firmware update.
It seems to create a bottleneck in the whole system by limiting the full interfacing of the pcie/nvme SSD, whether that be a lane bandwidth issue or an internal SSD caching issue, in OEM (AND) 3rd party blade SSDs!
As I say, I can provide data as proof but just take my word for it. I've also tried around 8 different SSDs, varying from the original SSD that came in it from factory, to OWC X2 who claim guarantee to work, to most Samsung aftermarket models(970,980,970evo,970evo plus, 980 pro), WD blacks, blues, you name it. Most let you install the OS and will migrate the data fine. And will tend to appear to work pretty slick on basic tasks like browsing, videos, etc. But as soon as you try to do some CPU intensive tasks, like stream via OBS, it just gets completely overwhelmed and majorly struggles to multitask.
The weird part is that using BlackMagic Disk Speed test on all of the 3rd party SSDs yields great results! Circa 2500Mb/s read/write on average, some 3000+. But it just doesn't perform well at all in practice.
Tried all types of RAM, OEM, OWC, bla bla...all possible versions of macOS, fresh installs, time machine restores....but firmware just cannot go backwards..
Tried swapping peripherals, USB hubs, nothing plugged in....all the same outcome.
Compare that to my other machine of exact same spec, running a Samsung 970 EVO Plus 1TB, and it can run multiple processes at once without breaking a sweat. OBS, Ableton, Logic Pro,5 separate web browsers....
E.g. OBS runs at around 6-12% CPU, even with other tasks running, on a high load scene on my good iMac while streaming AND recording.
The bad iMac board runs at around 60+% CPU load with OBS open alone! Which spikes up and down hitting 100% load frequently!
I think I have tried everything I can think of anyway, open to more suggestions, but I bet I've tried it.
In the meantime, I await arrival of another machine of same spec I've sourced which the owner confirmed is stuck at the fabled 170.00.... even though he updated to Monterey, so fingers crossed!
So in conclusion, I'd personally be thankful if my iMac 27 inch 5K Late 2015 firmware is not in fact updating fully!! If it ain't broke.......
Last edited:
I have the same machine upgraded to the latest firmware and it runs great so it is something particular to your machine. With that firmware you should have access to the newer recovery facility. I haven’t tried to load an older OS but that is where you would do it. I assume you have reset everything pram, smc?
Have in mind that only 4 years ago the Intel spectre bug has been found. This cpus are affected by this!
Maybe there was an Intel microcode update processed with this update? Your i7 should be more affected then the i5s because of the hyperthreading.
So you said you have both, a patched and an unpatched system, go check the microcodeversion in terminal with "sysctl machdep.cpu" and compare the versions show under "machdep.cpu.microcode_version".
Are they still the same?
Maybe there was an Intel microcode update processed with this update? Your i7 should be more affected then the i5s because of the hyperthreading.
So you said you have both, a patched and an unpatched system, go check the microcodeversion in terminal with "sysctl machdep.cpu" and compare the versions show under "machdep.cpu.microcode_version".
Are they still the same?
Ah now this is an interesting point. I'll check this today, is it something I can change if needed? Thanks
The 'GOOD' iMac:
machdep.cpu.leaf7_feature_bits: 43806655 0
machdep.cpu.leaf7_feature_bits_edx: 2617255424
machdep.cpu.extfeature_bits: 1241984796928
machdep.cpu.signature: 329443
machdep.cpu.brand: 0
machdep.cpu.features: FPU VME DE PSE TSC MSR PAE MCE CX8 APIC SEP MTRR PGE MCA CMOV PAT PSE36 CLFSH DS ACPI MMX FXSR SSE SSE2 SS HTT TM PBE SSE3 PCLMULQDQ DTES64 MON DSCPL VMX EST TM2 SSSE3 FMA CX16 TPR PDCM SSE4.1 SSE4.2 x2APIC MOVBE POPCNT AES PCID XSAVE OSXSAVE SEGLIM64 TSCTMR AVX1.0 RDRAND F16C
machdep.cpu.leaf7_features: RDWRFSGS TSC_THREAD_OFFSET SGX BMI1 HLE AVX2 SMEP BMI2 ERMS INVPCID RTM FPU_CSDS MPX RDSEED ADX SMAP CLFSOPT IPT MDCLEAR TSXFA IBRS STIBP L1DF SSBD
machdep.cpu.extfeatures: SYSCALL XD 1GBPAGE EM64T LAHF LZCNT PREFETCHW RDTSCP TSCI
machdep.cpu.logical_per_package: 16
machdep.cpu.cores_per_package: 8
machdep.cpu.microcode_version: 226
machdep.cpu.processor_flag: 1
machdep.cpu.mwait.linesize_min: 64
machdep.cpu.mwait.linesize_max: 64
machdep.cpu.mwait.extensions: 3
machdep.cpu.mwait.sub_Cstates: 1319200
machdep.cpu.thermal.sensor: 1
machdep.cpu.thermal.dynamic_acceleration: 1
machdep.cpu.thermal.invariant_APIC_timer: 1
machdep.cpu.thermal.thresholds: 2
machdep.cpu.thermal.ACNT_MCNT: 1
machdep.cpu.thermal.core_power_limits: 1
machdep.cpu.thermal.fine_grain_clock_mod: 1
machdep.cpu.thermal.package_thermal_intr: 1
machdep.cpu.thermal.hardware_feedback: 0
machdep.cpu.thermal.energy_policy: 1
machdep.cpu.xsave.extended_state: 31 832 1088 0
machdep.cpu.xsave.extended_state1: 15 832 256 0
machdep.cpu.arch_perf.version: 4
machdep.cpu.arch_perf.number: 4
machdep.cpu.arch_perf.width: 48
machdep.cpu.arch_perf.events_number: 7
machdep.cpu.arch_perf.events: 0
machdep.cpu.arch_perf.fixed_number: 3
machdep.cpu.arch_perf.fixed_width: 48
machdep.cpu.cache.linesize: 64
machdep.cpu.cache.L2_associativity: 4
machdep.cpu.cache.size: 256
machdep.cpu.tlb.inst.large: 8
machdep.cpu.tlb.data.small: 64
machdep.cpu.tlb.data.small_level1: 64
machdep.cpu.address_bits.physical: 39
machdep.cpu.address_bits.virtual: 48
machdep.cpu.core_count: 4
machdep.cpu.thread_count: 8
machdep.cpu.tsc_ccc.numerator: 334
machdep.cpu.tsc_ccc.denominator: 2
The 'BAD' iMac:
machdep.cpu.tsc_ccc.numerator: 334
machdep.cpu.tsc_ccc.denominator: 2
machdep.cpu.mwait.linesize_min: 64
machdep.cpu.mwait.linesize_max: 64
machdep.cpu.mwait.extensions: 3
machdep.cpu.mwait.sub_Cstates: 1319200
machdep.cpu.thermal.sensor: 1
machdep.cpu.thermal.dynamic_acceleration: 1
machdep.cpu.thermal.invariant_APIC_timer: 1
machdep.cpu.thermal.thresholds: 2
machdep.cpu.thermal.ACNT_MCNT: 1
machdep.cpu.thermal.core_power_limits: 1
machdep.cpu.thermal.fine_grain_clock_mod: 1
machdep.cpu.thermal.package_thermal_intr: 1
machdep.cpu.thermal.hardware_feedback: 0
machdep.cpu.thermal.energy_policy: 1
machdep.cpu.xsave.extended_state: 31 832 1088 0
machdep.cpu.xsave.extended_state1: 15 832 256 0
machdep.cpu.arch_perf.version: 4
machdep.cpu.arch_perf.number: 4
machdep.cpu.arch_perf.width: 48
machdep.cpu.arch_perf.events_number: 7
machdep.cpu.arch_perf.events: 0
machdep.cpu.arch_perf.fixed_number: 3
machdep.cpu.arch_perf.fixed_width: 48
machdep.cpu.cache.linesize: 64
machdep.cpu.cache.L2_associativity: 4
machdep.cpu.cache.size: 256
machdep.cpu.tlb.inst.large: 8
machdep.cpu.tlb.data.small: 64
machdep.cpu.tlb.data.small_level1: 64
machdep.cpu.address_bits.physical: 39
machdep.cpu.address_bits.virtual: 48
machdep.cpu.max_basic: 22
machdep.cpu.max_ext: 2147483656
machdep.cpu.vendor: GenuineIntel
machdep.cpu.brand_string: Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz
machdep.cpu.family: 6
machdep.cpu.model: 94
machdep.cpu.extmodel: 5
machdep.cpu.extfamily: 0
machdep.cpu.stepping: 3
machdep.cpu.feature_bits: 9221959987971750911
machdep.cpu.leaf7_feature_bits: 43806655 0
machdep.cpu.leaf7_feature_bits_edx: 3154128384
machdep.cpu.extfeature_bits: 1241984796928
machdep.cpu.signature: 329443
machdep.cpu.brand: 0
machdep.cpu.features: FPU VME DE PSE TSC MSR PAE MCE CX8 APIC SEP MTRR PGE MCA CMOV PAT PSE36 CLFSH DS ACPI MMX FXSR SSE SSE2 SS HTT TM PBE SSE3 PCLMULQDQ DTES64 MON DSCPL VMX EST TM2 SSSE3 FMA CX16 TPR PDCM SSE4.1 SSE4.2 x2APIC MOVBE POPCNT AES PCID XSAVE OSXSAVE SEGLIM64 TSCTMR AVX1.0 RDRAND F16C
machdep.cpu.leaf7_features: RDWRFSGS TSC_THREAD_OFFSET SGX BMI1 HLE AVX2 SMEP BMI2 ERMS INVPCID RTM FPU_CSDS MPX RDSEED ADX SMAP CLFSOPT IPT MDCLEAR TSXFA IBRS STIBP L1DF ACAPMSR SSBD
machdep.cpu.extfeatures: SYSCALL XD 1GBPAGE EM64T LAHF LZCNT PREFETCHW RDTSCP TSCI
machdep.cpu.logical_per_package: 16
machdep.cpu.cores_per_package: 8
machdep.cpu.microcode_version: 240
machdep.cpu.processor_flag: 1
machdep.cpu.core_count: 4
machdep.cpu.thread_count: 8
machdep.cpu.leaf7_feature_bits: 43806655 0
machdep.cpu.leaf7_feature_bits_edx: 2617255424
machdep.cpu.extfeature_bits: 1241984796928
machdep.cpu.signature: 329443
machdep.cpu.brand: 0
machdep.cpu.features: FPU VME DE PSE TSC MSR PAE MCE CX8 APIC SEP MTRR PGE MCA CMOV PAT PSE36 CLFSH DS ACPI MMX FXSR SSE SSE2 SS HTT TM PBE SSE3 PCLMULQDQ DTES64 MON DSCPL VMX EST TM2 SSSE3 FMA CX16 TPR PDCM SSE4.1 SSE4.2 x2APIC MOVBE POPCNT AES PCID XSAVE OSXSAVE SEGLIM64 TSCTMR AVX1.0 RDRAND F16C
machdep.cpu.leaf7_features: RDWRFSGS TSC_THREAD_OFFSET SGX BMI1 HLE AVX2 SMEP BMI2 ERMS INVPCID RTM FPU_CSDS MPX RDSEED ADX SMAP CLFSOPT IPT MDCLEAR TSXFA IBRS STIBP L1DF SSBD
machdep.cpu.extfeatures: SYSCALL XD 1GBPAGE EM64T LAHF LZCNT PREFETCHW RDTSCP TSCI
machdep.cpu.logical_per_package: 16
machdep.cpu.cores_per_package: 8
machdep.cpu.microcode_version: 226
machdep.cpu.processor_flag: 1
machdep.cpu.mwait.linesize_min: 64
machdep.cpu.mwait.linesize_max: 64
machdep.cpu.mwait.extensions: 3
machdep.cpu.mwait.sub_Cstates: 1319200
machdep.cpu.thermal.sensor: 1
machdep.cpu.thermal.dynamic_acceleration: 1
machdep.cpu.thermal.invariant_APIC_timer: 1
machdep.cpu.thermal.thresholds: 2
machdep.cpu.thermal.ACNT_MCNT: 1
machdep.cpu.thermal.core_power_limits: 1
machdep.cpu.thermal.fine_grain_clock_mod: 1
machdep.cpu.thermal.package_thermal_intr: 1
machdep.cpu.thermal.hardware_feedback: 0
machdep.cpu.thermal.energy_policy: 1
machdep.cpu.xsave.extended_state: 31 832 1088 0
machdep.cpu.xsave.extended_state1: 15 832 256 0
machdep.cpu.arch_perf.version: 4
machdep.cpu.arch_perf.number: 4
machdep.cpu.arch_perf.width: 48
machdep.cpu.arch_perf.events_number: 7
machdep.cpu.arch_perf.events: 0
machdep.cpu.arch_perf.fixed_number: 3
machdep.cpu.arch_perf.fixed_width: 48
machdep.cpu.cache.linesize: 64
machdep.cpu.cache.L2_associativity: 4
machdep.cpu.cache.size: 256
machdep.cpu.tlb.inst.large: 8
machdep.cpu.tlb.data.small: 64
machdep.cpu.tlb.data.small_level1: 64
machdep.cpu.address_bits.physical: 39
machdep.cpu.address_bits.virtual: 48
machdep.cpu.core_count: 4
machdep.cpu.thread_count: 8
machdep.cpu.tsc_ccc.numerator: 334
machdep.cpu.tsc_ccc.denominator: 2
The 'BAD' iMac:
machdep.cpu.tsc_ccc.numerator: 334
machdep.cpu.tsc_ccc.denominator: 2
machdep.cpu.mwait.linesize_min: 64
machdep.cpu.mwait.linesize_max: 64
machdep.cpu.mwait.extensions: 3
machdep.cpu.mwait.sub_Cstates: 1319200
machdep.cpu.thermal.sensor: 1
machdep.cpu.thermal.dynamic_acceleration: 1
machdep.cpu.thermal.invariant_APIC_timer: 1
machdep.cpu.thermal.thresholds: 2
machdep.cpu.thermal.ACNT_MCNT: 1
machdep.cpu.thermal.core_power_limits: 1
machdep.cpu.thermal.fine_grain_clock_mod: 1
machdep.cpu.thermal.package_thermal_intr: 1
machdep.cpu.thermal.hardware_feedback: 0
machdep.cpu.thermal.energy_policy: 1
machdep.cpu.xsave.extended_state: 31 832 1088 0
machdep.cpu.xsave.extended_state1: 15 832 256 0
machdep.cpu.arch_perf.version: 4
machdep.cpu.arch_perf.number: 4
machdep.cpu.arch_perf.width: 48
machdep.cpu.arch_perf.events_number: 7
machdep.cpu.arch_perf.events: 0
machdep.cpu.arch_perf.fixed_number: 3
machdep.cpu.arch_perf.fixed_width: 48
machdep.cpu.cache.linesize: 64
machdep.cpu.cache.L2_associativity: 4
machdep.cpu.cache.size: 256
machdep.cpu.tlb.inst.large: 8
machdep.cpu.tlb.data.small: 64
machdep.cpu.tlb.data.small_level1: 64
machdep.cpu.address_bits.physical: 39
machdep.cpu.address_bits.virtual: 48
machdep.cpu.max_basic: 22
machdep.cpu.max_ext: 2147483656
machdep.cpu.vendor: GenuineIntel
machdep.cpu.brand_string: Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz
machdep.cpu.family: 6
machdep.cpu.model: 94
machdep.cpu.extmodel: 5
machdep.cpu.extfamily: 0
machdep.cpu.stepping: 3
machdep.cpu.feature_bits: 9221959987971750911
machdep.cpu.leaf7_feature_bits: 43806655 0
machdep.cpu.leaf7_feature_bits_edx: 3154128384
machdep.cpu.extfeature_bits: 1241984796928
machdep.cpu.signature: 329443
machdep.cpu.brand: 0
machdep.cpu.features: FPU VME DE PSE TSC MSR PAE MCE CX8 APIC SEP MTRR PGE MCA CMOV PAT PSE36 CLFSH DS ACPI MMX FXSR SSE SSE2 SS HTT TM PBE SSE3 PCLMULQDQ DTES64 MON DSCPL VMX EST TM2 SSSE3 FMA CX16 TPR PDCM SSE4.1 SSE4.2 x2APIC MOVBE POPCNT AES PCID XSAVE OSXSAVE SEGLIM64 TSCTMR AVX1.0 RDRAND F16C
machdep.cpu.leaf7_features: RDWRFSGS TSC_THREAD_OFFSET SGX BMI1 HLE AVX2 SMEP BMI2 ERMS INVPCID RTM FPU_CSDS MPX RDSEED ADX SMAP CLFSOPT IPT MDCLEAR TSXFA IBRS STIBP L1DF ACAPMSR SSBD
machdep.cpu.extfeatures: SYSCALL XD 1GBPAGE EM64T LAHF LZCNT PREFETCHW RDTSCP TSCI
machdep.cpu.logical_per_package: 16
machdep.cpu.cores_per_package: 8
machdep.cpu.microcode_version: 240
machdep.cpu.processor_flag: 1
machdep.cpu.core_count: 4
machdep.cpu.thread_count: 8
So the good machine is running microcode version 226 and the bad is running 240. Can I edit the BOOT ROM part this concerns?
I've read about people doing this with macBooks, but myself would be frightened to do so.
As the cpu is not soldered, it could be changed. But maybe the microcode is loaded at startup in cpu. As far as I know, Windows for example is upgrading microcode while starting the OS.
So maybe someone knows about Macs and the was they handle the microcode? Maybe the CPU is programmed with the new microcode at firmwareupgradetime, or each time at startup....
But I am a little glad to hear that it seems not to be Apple who is responsible for the lack of systempower but Intel. Nevertheless, this is a sad story...
As the cpu is not soldered, it could be changed. But maybe the microcode is loaded at startup in cpu. As far as I know, Windows for example is upgrading microcode while starting the OS.
So maybe someone knows about Macs and the was they handle the microcode? Maybe the CPU is programmed with the new microcode at firmwareupgradetime, or each time at startup....
But I am a little glad to hear that it seems not to be Apple who is responsible for the lack of systempower but Intel. Nevertheless, this is a sad story...