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Slow like molasses, 5 MB/s on 1 Gb fiber, seems like Apple has issues lately, I've always been downloading at a minimum of 10X that speed.
Or Big Sur network bugs, last few beta's downloading started fast, like 40-50 MB/s, it slowly dropped, second by second, I restarted the download a few times, it even got into 110's of KB per second, now it started at 2 MB/s, and it went up second by second, stable at about 10 to 11 MB/s.
Hope it's networking bugs.
 
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Slow like molasses, 5 MB/s on 1 Gb fiber, seems like Apple has issues lately, I've always been downloading at a minimum of 10X that speed.
About OK, downloading from Catalina (6MB/s, which is my nominal link speed).
But then terminated at 5.5GB - starting over - and again.
 
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... I advise to don't use more on BigSur any spoofing opencore setup for OTA updates, because apple especially with ARM might change the EFI SMC "FirmwareUpdate.pkg post script", their "firmware dictionary keys" or csr-active-config or "nvram firmware boot-args" or "plist kernel flags" or Firmware.scap file to crossflash your unsupported BigSur Mac EFI SMC firmware regardless of how much safe is the opencore config.plist made.
@jackluke Just to double-check, are you pretty sure that the issue only applies to OTA updates? What about using OC spoofing to let an unpatched full installer run? (Isn't that also possibly able to install firmware updates?) Thanks.
 
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@jackluke Just to double-check, are you pretty sure that the issue only applies to OTA updates? What about using OC spoofing to let an unpatched full installer run? (Isn't that also possibly able to install firmware updates?) Thanks.
Which particular OC config are you talking about?

This is irrelevant as long as you are not spoofing the board-id of a supported machine. Using the OC version made for the iMac 2009 and 2010 and MacBook Pro 6.x and the OC made for the NVIDIA K610M/K1100M/K2100M backlight control should cause no harm to the systems.

P.S.: Just installing BS1102 on my iMac 27 late 2009 using such an OC package...
 
@jackluke Just to double-check, are you pretty sure that the issue only applies to OTA updates? What about using OC spoofing to let an unpatched full installer run? (Isn't that also possibly able to install firmware updates?) Thanks.

The EFI firmware issue applies to any OC spoofing during the stage1 or stage2 installer, using an unpatched full installer is equivalent to an OTA update, only safer method to install BigSur is through ASentientBot Hax3.app or HaxLib.dylib (that requires AMFI disabled) already included in micropatcher or any other BigSur patcher available.
 
BS Beta 11.0 (20B5022a) on an iMac 11,1 using the OC DSDT patch and micro patcher 0.5.0 and some unreleased personal adjustments to auto detect and patch the iMac family....

Thanks a lot @khronokernel and @Barry K. Nathan and @jackluke !

(it was the link @jackluke posted an hour ago....)
 

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So as already reported this 11.0.1 Release Candidate has still a Beta naming, also its BaseSystem.dmg , all newer core system files have been compiled on 30 October by apple.

I decided to release my newer BigSur BaseSystem fix that includes also some my patching bash apps (attached a summary table) that require a minimal keyboard interaction.

I also added some my modified custom apps, for example based on hholtmann's smcFanControl I wrote a script that should allow to detect the average CPU temperature from recovery environment and increase fans RPM speed.

I attached a pdf to explain in more detail my BigSurFixes.

Guides, patched files and patching methods :

- @ASentientBot HaxLib.dylib, Nvidia Tesla fixes, 0xfff boot.efi , apfs_systemsnapshot (to fix “sudo mount -uw /“) , nvenet.kext and IOHIDFamily (single user mode patch)
- @parrotgeek1 LegacyUSBInjector.kext
- acidanthera opencore developers
- @khronokernel ACPI patch for Arrandale Intel architecture through opencore
- @Syncretic telemetrap.kext , AAAMouSSE.kext and tips for adding Legacy USB IOKitPersonalities
- @Barry K. Nathan method of replacing kext already present on a BaseSystem (with ULFO compression), deleting snapshots and gnuefi binaries similar to setvars function
- @cdf OpenCore thread on MacRumors
- @fabioroberto for Nvidia kp fix on dualGPUs Arrandale MacBookPro
- @hvds Legacy USB HID patch debugging and stage2 macOS Installer testing with an external root Legacy USB device
- @Ausdauersportler for testing BaseSystem Legacy USB fix on iMac with upgraded Metal GPU
 

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If your iMac11,1 has a Lynnfield/Nehalem cpu, you should use OpenCore boot loader with @khronokernel SSDT patch for ACPI kp to boot the BigSur installer.

My iMac does indeed have Nehalem, i7-860. Yes, I had previously added the SSDT-CPBG.aml to EFI/OC/ACPI directory of my OpenCore booter.

Moreover some late 2009 Mac even if with APFS firmware they still embed Legacy USB devices (requiring an additional LegacyUSBInjector patch) so I made a preconfigured opencore setup with khronokernel SSDT patch and Legacy USB (to encounter few issues with "Legacy USB BKE" install BigSur on internal SATA disk).

I would like to try your pre-configured OpenCore setup, but I don't see anything to download when I click your Discord link.

Make a stock BigSur createinstallmedia installer, then try this: https://forums.macrumors.com/thread...unsupported-macs-thread.2242172/post-29138842

From your post, I need to run the commands from a Big Sur terminal... but since I'm unable to install Big Sur, I can't try that.

The OpenCore4b1 setup is totally safe because doesn't contain any spoofing for OTA BigSur updates so no risk of firmware update during stage2 installer.

If the OpenCore4b1 is your pre-configured setup, I would really like to try. If it's easier, please send me a quick PM here. I can provide an upload folder if that is easier than Discord (?) or other way.

Thank so much.. I feel like I'm really close!
 
My iMac does indeed have Nehalem, i7-860. Yes, I had previously added the SSDT-CPBG.aml to EFI/OC/ACPI directory of my OpenCore booter.

From your post, I need to run the commands from a Big Sur terminal... but since I'm unable to install Big Sur, I can't try that.

If the OpenCore4b1 is your pre-configured setup, I would really like to try. If it's easier, please send me a quick PM here. I can provide an upload folder if that is easier than Discord (?) or other way.

Thank so much.. I feel like I'm really close!

Try my latest BigSur BaseSystem fix and it should work on your Nehalem cpu.

You need first to make a stock createinstallmedia USB BigSur installer with this method:
Code:
sudo /Applications/Install\ macOS\ Big\ Sur\ Beta.app/Contents/Resources/createinstallmedia --volume /Volumes/“YourUSBLabel”

Then once the stock Installer is made, apply first the “BigSurBaseSystem fix”, then unplug and plug again your USB drive and apply “BigSurBaseSystem fix2” command, after done you can boot holding alt-option key from apple startup manager, from opencore or any bootloader.
 
I just saw that Mr Macintosh had this in his release notes regarding BS 11.0.1 RC (20B5022a). Don't know how this effects us??

Kernel​

KNOWN ISSUES​

  • Installing a new kernel extension requires signing in as an Admin user. You must also restart your Mac to load the extension. Kernel extensions using certain deprecated KPIs won’t be loaded. For more information, see Deprecated Kernel Extensions and System Extension Alternatives. (55068348)Workaround: During development, you can temporarily disable System Integrity Protection to allow these deprecated kernel extensions to load.
  • New in macOS Big Sur 11.0.1 Release Candidate, the system ships with a built-in dynamic linker cache of all system-provided libraries. As part of this change, copies of dynamic libraries are no longer present on the filesystem. Code that attempts to check for dynamic library presence by looking for a file at a path or enumerating a directory will fail. Instead, check for library presence by attempting to dlopen() the path, which will correctly check for the library in the cache. (62986286)
  • Use only absolute paths with the --volume-root option of kmutil, and don’t use a trailing /. (63773848)
  • Symbols exported by both xnu and Apple kernel extensions will change. Recompile your kernel extension with each update to macOS Big Sur 11.0.1 Release Candidate to ensure compatibility. (64262563)

 
Try my latest BigSur BaseSystem fix and it should work on your Nehalem cpu.

You need first to make a stock createinstallmedia USB BigSur installer with this method:
Code:
sudo /Applications/Install\ macOS\ Big\ Sur\ Beta.app/Contents/Resources/createinstallmedia --volume /Volumes/“YourUSBLabel”

Then once the stock Installer is made, apply first the “BigSurBaseSystem fix”, then unplug and plug again your USB drive and apply “BigSurBaseSystem fix2” command, after done you can boot holding alt-option key from apple startup manager, from opencore or any bootloader.
So close! But still not yet :(

I followed your instructions, exactly.
1) Create new BS bootable installer, to USB
2) Downloaded and applied BigSurBaseSystem fix
3) Unplugged, plugged USB back in
4) Applied BigSurBaseSystem fix2
5) Reboot into Catalina Loader, pick Macintosh HD from OC bootpicker
6) Launch Install macOS Big Sur application directly from USB
7) Installer begins, but errors out at same screen, i.e. "Your Mac needs a firmware update.... Please select a Mac OS Extended (Journaled) volume instead"

I'm thinking I need to find/use OpenCore4b1, if someone could kindly point me in the right direction. I'm using iMac 11,1 Late 2009 27" i7-860 with patched K2100M. Runs perfectly fine with OC 0.6.0 on High Sierra 10.13.6.


EDIT: I found your OpenCore4b1 on post #5504, and now my error when installing is "The update cannot be installed on this computer"

EDIT#2 (sorry) - I think it's working :) After Reboot/Option, I pick my Catalina Loader, then from OC boot picker, I choose Install MacOS Big Sur

EDIT #3 nope - same error "The update cannot be installed..." even when booting from OC Big Sur installer. I even tried installing Big Sur to an external SSD (via USB), formatted as APFS, GUID Partition Map.



Even booting from OpenCoreAPFSloader4b1, then into Install macOS Big Sur Beta USB via the OC boot picker, I cannot get it to work.
 
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Updated my late 2013 iMac from 11.0.1 B1 to this RC using big-sur-micropatcher 0.5.0. One thing noticed since the restart, there is *considerable* disk activity going which in some cases is making the system barely usable. So, not sure what is going on under the hood, but will see if it settles down over the next period
 
So close! But still not yet :(

I followed your instructions, exactly.
1) Create new BS bootable installer, to USB
2) Downloaded and applied BigSurBaseSystem fix
3) Unplugged, plugged USB back in
4) Applied BigSurBaseSystem fix2
5) Reboot into Catalina Loader, pick Macintosh HD from OC bootpicker
6) Launch Install macOS Big Sur application directly from USB
7) Installer begins, but errors out at same screen, i.e. "Your Mac needs a firmware update.... Please select a Mac OS Extended (Journaled) volume instead"

I'm thinking I need to find/use OpenCore4b1, if someone could kindly point me in the right direction. I'm using iMac 11,1 Late 2009 27" i7-860 with patched K2100M. Runs perfectly fine with OC 0.6.0 on High Sierra 10.13.6.


EDIT: I found your OpenCore4b1 on post #5504, and now my error when installing is "The update cannot be installed on this computer"

EDIT#2 (sorry) - I think it's working :) After Reboot/Option, I pick my Catalina Loader, then from OC boot picker, I choose Install MacOS Big Sur

EDIT #3 nope - same error "The update cannot be installed..." even when booting from OC Big Sur installer. I even tried installing Big Sur to an external SSD (via USB), formatted as APFS, GUID Partition Map.



Even booting from OpenCoreAPFSloader4b1, then into Install macOS Big Sur Beta USB via the OC boot picker, I cannot get it to work.

Before installing or updating BigSur on any unsupported Mac you should apply the ASentientBot Hax3 HaxLib.dylib installer fix also included in BaseSystem fix , you can apply it quickly from Installer Utilities menu or directly from main menu Hax3 fix (clicking on upper right finder menu) or even opening terminal and typing /V*/I*/H*

If you are not upgrading a previous BigSur it's advisable to erase first the container as APFS .
 
Big Sur (B11.01) on iMac 11,x and 12,x


Everybody with an iMac 11,x and new metal graphics card interested in trying Big Sur on an iMac please read this post to get an idea which OpenCore version to be used and how to patch...

Users of the 12,x do not need a special OC patch or better no OC at all to install, but I would strongly recommend all users of AMD cards using OC to spoof the iMacPro1,1 ID to change the config.plist during the installation process to avoid getting an unwanted firmware update. Just use an NVIDIA plist file or disable spoofing. As pointed out before the blocking of firmware upgrades through OC might not work at all.

To use the latest 0.5.0 micro patcher you have to put the attached zipped extension files into the payloads/kexts folder before patching the USB thumb drive in the downloaded micro patcher or after patching on the USB thumb drive in the kexts folder and use the attached version of the patch-kext.sh script.

Model detection is automated, patches are selected according to hardware found on the system (NVIDIA or AMD). User of NVIDIA K610M/K1100M/K2100M cards have to currently use the --useOC option. In this case no versions of BacklightFixup.kext, Whatevergreen.kext and Lilu.kext will be installed, these will be injected via OC. I cannot detect this special card type currently automatically. The same happens on all systems with AMD cards.

All users of 11,x iMacs will need OC all the time to boot the Big Sur. So I assume all the extensions just mentioned above will be injected there, too. Bottom line: You will need OC to use Big Sur! There is currently no way around it.

All this needs a deeper knowledge of the MacOS and the usage go Terminal command line. Who is not really familiar with this should stay away from this experiment.

Any questions?

Have fun!

Notes:

  1. Make the OC the standard boot object before starting the installer. It will come back there some times during the reboots.
  2. AMD cards are AMD Polaris cards and metal compatible
  3. NVIDIA cards are Kepler GPU based cards and metal compatible
  4. Installing Big Sur on an original iMac 11,x or 12,x with Apple branded ATI/AND Radeon 4xxx, 5xxx, 6xxx cards will be possible, the result barely usable. There is no graphics acceleration and there will be no for all times
  5. about the --useOC option: all iMac11,x system need OC and so this option will be chosen automatically. 2011 systems may use AMD Polaris cards (use--useOC), the already mentioned NVIDIA K610M/K1100M/K2100M card (use --useOC, too) or other NVIDIA cards not needing OC.
 

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Hi all,

macOS Big Sur 11.0.1 20B5022a successfully installed on cMP5,1 with micropatcher 0.5.0 (on top of 20B5012d)

Everything seems to work, Airdrop, Handoff and H264 acceleration

View attachment 1361217


this release has regressed on an important point: the welcome screen, the default wallpaper is back, even if you change it. I don't know if there were other points that regressed, but that was the first thing I noticed when installing this RC.
 
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