/BigSurfixes

Big Sur fixes for unsupported Mac aka BigSur BaseSystem fix

Primary LanguageShell

BigSurfixes

BigSurBaseSystemfix external recovery patcher (from here you can even delete the com.apple.os.update locked snapshot booting resulting in a working mount -uw / to make any system modifications, this feature requires an unsealed System that is through ASentientBot Hax Installer fix), updated for generic BigSur 11.x beta, simply restore through DiskUtility this DMG to a minimum 1 GB USB drive (or a 16 GB USB to add also the updated Beta installer): Dropbox link

besides DiskUtility you can use also its Apple Software Restore command line :

sudo asr -source ~/Downloads/BigSurBaseSystemfix.dmg -erase -noverify -target /Volumes/YourUSBLabel

for an updated full installer:

  • restore the BigSurBaseSystemfix.dmg to a 16 GB USB empty drive (or to a 16 GB HFS+ partition external to an APFS container)
  • download any 11.x beta InstallAssistant.pkg (12,4 GB) and run it to make the unpacked apple "macOS Install app" (other additional 12,5 GB) in its the default macOS (HighSierra, Mojave, Catalina, BigSur) Applications folder
  • launch the BigSurSharedSupportfix that should automatically copy the updated 12,3 GB SharedSupport.dmg (that is where the stage2 installer is stored) to the 16 GB USB drive (that acts as an updated BaseSystemfix Installer)
  • at reboot from apple startup manager or any bootloader it should work to boot "BigSurBaseSystemfix" with an updated "stage2 macOS Installer", hence you can install current system

BigSur Installer BaseSystem fix updated for 11.0.1 release candidate to work with non-APFS or legacy USB Penryn Core2Duo, Arrandale i3 i5 i7 (also for other Intel Architectures) this new version contains many useful patching apps: https://github.com/jacklukem/BigSurfixes/releases/

Quick guide: https://github.com/jacklukem/BigSurfixes/blob/master/BigSurBaseSystemfix.pdf

Summary table: alt text

additional tips if you can't boot the BaseSystem fix: https://forums.macrumors.com/threads/macos-11-big-sur-on-unsupported-macs-thread.2242172/post-29214703

Arrandale i5 i7 (MacBookPro), Clarksdale i3 and Lynnfield i5 i7 (iMac), Nehalem and Westmere (MacPro) Intel Xeon architecture cpus are now supported but require booting from apple startup manager (alt-option key) through OpenCore with khronokernel patch also included on BaseSystemfix (Update OC config 4b1) or can download from here to use an external USBopencore (OpenCore4b1 or OpenCore3b1) : https://forums.macrumors.com/threads/macos-11-big-sur-on-unsupported-macs-thread.2242172/post-29138842

Installing BigSur non-APFS Mac legacy USB

Currently for non-APFS firmware Mac when installing BigSur on external legacy USB host target, while stage2 installer has been fixed, there is still an issue with stage3 installer, this occurs with a clean BigSur installation, here are some explaination to workaround this issue :

  • simply installing BigSur on internal SATA target disk the installation will proceed with few efforts
  • for a clean install on external legacy USB target, try to erase the disk as HFS+ (then the "stage2 installer fix" should auto convert to APFS)
  • to use stage2 and stage3 installer without fixes (or simply through OpenCoreAPFSloader to detect the hidden APFS "macOS Installer") on those non-APFS Mac you should install BigSur on internal SATA disk, then through CCC or BigSur installer DiskUtility you can clone the installed BigSur (it requires at least 50 GB) to external USB and it will work (after applied the "BigSurFixes legacy USB patches")
  • you could even install BigSur on internal SATA disk, then unplug and plug it externally through USB and it will work
  • the stage3 installer on external USB target is skippable or fixable when updating a previous already installed Catalina or BigSur, because it requires an already "apple setup done" (to fix the "apfs firmlink" issues) that is a root account for the APFS Data Volume

without a Metal GPU currently graphics rendering is enough slow, but there are some workaround to improve a bit performance:

alt text

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click here for more detail

These previous fixes are now merged with BigSur Installer BaseSystem legacy USB fix

Making a patched BigSur Installer through BaseSystem legacy USB fix updated for beta 9 and beta 10 mainly for non-APFS or legacy USB Penryn Core2Duo through a stock createinstallmedia or opencore

https://forums.macrumors.com/threads/macos-11-big-sur-on-unsupported-macs-thread.2242172/post-28973673

The stage2 installer will continue when target is an internal SATA disk, but on non-APFS or legacy USB when targeting an external USB this should be applied from Mojave or Catalina: https://github.com/jacklukem/BigSurfixes/raw/master/BigSur%20BaseSystem%20stage2%20installer%20fix.zip

To fix USBopencore "exiting efiboot", boot from BigSurInstaller (BaseSystem fix) or from Recovery with CMD+S then try this: https://forums.macrumors.com/threads/macos-11-big-sur-on-unsupported-macs-thread.2242172/post-28948321

you could skip stage3 installer (that is seal and system snapshot) but for non-APFS or legacy USB you need this to boot with CMD+S and exit: https://github.com/jacklukem/BigSurfixes/blob/master/penryn%20c2d%20bigsur%20beta6/BKE%20kc%20b9%20patched.zip

After USBopencore kext patching to boot without opencore and assign BigSur labels use this method: https://forums.macrumors.com/threads/macos-11-big-sur-on-unsupported-macs-thread.2242172/post-28957937

to download a BigSur full installer from Mojave or Catalina try this: https://forums.macrumors.com/threads/macos-11-big-sur-on-unsupported-macs-thread.2242172/post-28740283 or this: https://apps.apple.com/app/macos-11-0-beta/id1497794093?mt=12

tips to make a patched BigSur Utitilies menu: https://forums.macrumors.com/threads/macos-11-big-sur-on-unsupported-macs-thread.2242172/post-28987885

Big Sur fixes for unsupported Mac

to support Big Sur booting on non-APFS mac or APFS firmware mac

BigSur added the BootKernelExtensions.kc as the new kernelcache with new command kmutil

but kextcache command and prelinkedkernel are still working:

https://forums.macrumors.com/threads/macos-11-big-sur-on-unsupported-macs-thread.2242172/post-28610988

Currently these fixes still work for Big Sur beta 4 Build 20A5343i

also works for public beta 1 Build 20A5343j: http://swcdn.apple.com/content/downloads/29/11/001-35028-A_7VBLVEPJM9/fmewkm9mb99ja9cbqfp4scme3bzlaurv8v/InstallAssistant.pkg

(apple removed previous beta full installers but you can find them on internet with keyword DMG)

check here for versions info: https://en.wikipedia.org/wiki/MacOS_Big_Sur#Release_history

prelinkedkernel fixes don't work from beta 6 Build 20A5364e (BaseSystem legacy usb fix still works on beta 10)

you should use from this version my USBOpencore setup in repository and BootKernelExtensions.kc

There was an issue from beta 7, but from beta 9 Build 20A5384c Penryn Core2Duo can boot BigSur kernel

I uploaded some patched BKE to allow boot with CMD+S that should be copied on: /Volumes/Preboot/UUIDBigSur/boot/System/Library/KernelCollections/ https://github.com/jacklukem/BigSurfixes/tree/master/penryn%20c2d%20bigsur%20beta6

Here are the most updated Big Sur fixes (for BigSur beta 3 that works also for beta 4 Build 20A5343i):

The following guide is for manual patching, to apply the prelinkedkernel fix after BigSur Install:

diskutil apfs list

diskutil list | grep Preboot

(if have multiple separated APFS containers, just mount the largest MB Preboot Volume)

diskutil mount Preboot

diskutil info / | grep UUID

Locate your BigSur Data Volume UUID

replace the "prelinkedkernel fix" file in this path:

/Volumes/Preboot/UUID-BigSur/System/Library/CoreServices/

replace it also here: /Volumes/Preboot/UUID-BigSur/Library/Preferences/SystemConfiguration/

replace the "patched prelinkedkernel" (contains newer beta fixes also for any non-APFS Mac enabling Wifi for AirPortBrcm4331 cards) in this path:

/Volumes/Preboot/UUID-BigSur/System/Library/PrelinkedKernels/

For the "installer fix" make a BigSur USB Installer with createinstallmedia:

sudo /Applications/Install\ macOS\ Big\ Sur\ Beta.app/Contents/Resources/createinstallmedia --volume /Volumes/BigSurInstaller/

and replace the "installer fix" file in this path:

/Volumes/USBInstallerBigSur/Library/Preferences/SystemConfiguration/

I also included some "legacyusb fix for installer"

for rebuild BigSur kernelcache from single user mode copy both the .sh files on your root / BigSur disk and home folder that is the / BigSur Label - Data / Users / yourusername /

then from single user mode type : chmod 755 kcsingleuser.sh ; ./kcsingleuser.sh

(credit to ASentientBot for Hax.dylib fix for "Install macOS Beta.app" and "apfs_boot_util" to mount the BigSur Data Volume from single user mode, after using "apfs_boot_util" from single user mode apart the Data Volume also the Preboot Volume is available in this path /System/Volumes/)

Note: if you use my "prelinkedkernel fix command" directly from BigSur the Preboot Volume mount point is this:

/System/Volumes/Preboot/

(can notice this directly from BigSur with "ls /System/Volumes/" )

So I uploaded those modified scripts to run also directly from BigSur normal booting.

BigSur introduced also a new SIP for sealing the System Volume, to disable from any APFS firmware Mac simply boot the USB BigSur Installer (or BigSur Recovery), open terminal and type: "csrutil authenticated-root disable"

While instead to disable "csrutil authenticated-root" from a non-APFS or legacy USB mac, copy the "csrutil2" (or use the zip file) binary file to any USB MacOS Installer (minimum El Capitan when apple introduced SIP but should use an USB Catalina Installer because it has more recent SDK) in its root folder / , then boot from the macOS USB Installer, open a recovery terminal and type:

cd / ; mount -uw / ; chmod 755 csrutil2

./csrutil2 authenticated-root disable

Otherwise if you use a Catalina Recovery, copy the file on an external USB drive, then from Catalina recovery terminal:

cd /Volumes/ ; ls

cd YourUSBLabel

mount -uw /

chmod 755 csrutil2

./csrutil2 authenticated-root disable

(Note: for any raw file downloaded to use them just remove the .dms extension that is set from github)