Jump to content

Updated Tips and Observations for 11.2

3 posts in this topic

Recommended Posts

Some updated tips and observations concerning Big Sur 11.2 installation to an available APFS HDD container/partition.

Assumes an existing working ESP bootloader.
Any changes to the system files in recovery console require creating a new shapshot to be retained.


1. Go ahead and make your USB installer with OC 0.6.5 or later, but if you have an existing install of Catalina you can save time by starting the Big Sur installer directly from Catalina, choosing the target partition, and letting the installer copy over the install files rather than waiting on USB to boot and copy. You can then use the USB installer to reboot Big Sur as required to complete the installation.


2. If you are a linux multi-booter and using grub2 as your main bootloader, and if you have an existing Catalina install with a working chainloaded Open Core or Clover, suggest you don't disturb/break your existing bootloader by making tweaks for Big Sur.  You can make an additional small 200MB FAT32 partition on your HDD and put your Big Sur bootloader there and chainload it from grub.cfg. Run lsblk -f or sudo blockid from linux terminal and note the UUID of the Big Sur FAT32 bootloader partition you made.  Temporarily edit your boot grub.cfg and add the appropriate entry where xxxx-xxxx is your Big Sur FAT32 bootloader partition UUID:

for open core:


menuentry "Open_Core"{
    insmod part_gpt
    search --no-floppy --set=root --fs-uuid xxxx-xxxx
    chainloader /EFI/OC/OpenCore.efi  # or whatever path you use


or for clover:


menuentry "Clover"{
    insmod part_gpt
    search --no-floppy --set=root --fs-uuid xxxx-xxxx
    chainloader /EFI/CLOVER/CLOVERX64.efi  # or whatever path you use


This way you can easily edit/tweak your Big Sur bootloader settings without breaking your existing working ESP bootloader.  If you are not comfortable using an XML editor to edit config.plist, and you have Catalina installed, you can download ProperTree from github and launch it from Catalina.  Later you can modify your linux /etc/grub.d/40_custom to include any custom bootloader menuentries you want to keep, and then run update-grub.
3. When your install is finished and you are finally at the working desktop, you may want to make a backup. With Catalina this was easily done by using Disk Utility from a bootable USB installer to restore to an APFS formatted backup media.  The Big Sur Disk Utility ASR has repeatedly failed to replicate Big Sur and it appears Disk Utility from Catalina 10.15.6 can not perform this task with Big Sur APFS containers. You can, however, clone the entire Big Sur container to removable media with third party software. Alternatively, depending on the size of your AFPS container/partition and transfer rate, using dd can take quite a long time to do the backup.  If you clone to USB media and then boot the clone to test the backup on the same computer from which it was made, both the Big Sur USB clone and the Big Sur HDD container installation show up within disk utility, in the USB media area.


4. If your Open Core keyboard language is not properly configured the recovery console language may default to Chinese. The language selector button with drop down menu on the top right did not previously appear to permit language selection.  Despite the language issue, recovery terminal is available even if the menus default to Chinese.  Mount command does work and you can diskutil mountDisk diskXsY and then mount -uw /Volumes/thenameofyourBigSuruser to make the normally read-only volume writable (where x is the number of your Big Sur disk and y is the read-only slice from the mount command output).

Make any desired system file changes from the console and reseal (where X is your Big Sur volume name shown with mount command):


bless --folder /Volumes/X/System/Library/CoreServices --bootefi --create-snapshot


5.  If you have an existing Catalina installation with brew and numerous brew installed programs such as ntfs-3g, you can directly copy the brew files/programs (usr/local) to the corresponding file system locations within Big Sur and if necessary, manually create the soft links to enable programs.  If you need to write to the system file tree you can do this from the recovery console as previously referenced.

NTFS volumes will normally mount read-only but read-write can be enabled if the installed /sbin/mount_ntfs supports read/write:


From terminal make a mountpoint of your choice for each ntfs volume.  Example: sudo mkdir ~/ntfs
Unmount the target read-only ntfs volume where x is disk number and y is slice: sudo umount /dev/diskxsy

Mount ntfs volume as read-write: sudo mount -t ntfs -o rw,auto,nobrowse /dev/diskxsy ~/ntfs
Link to desktop: sudo ln -s ~/ntfs ~/Desktop/whatever_name_you_choose


Make sure finder is configured to show hard disks on the desktop.


Keep in mind that if you use ntfs-3g with osxfuse to automount ntfs volumes, install version 3.11.0 or later of osxfuse.  You may have to copy the ntfs-3g mount_ntfs binary directly to /sbin using recovery console.  Brew's ntfs-3g 2017.3.23_3 does not mount NTFS volumes with all files and folders visible.  You can use a prior Catalina Version, although it may be necessary to copy mount_ntfs directory to sbin.  Any changes made in recovery console should be followed by creating a new shapshot:  bless --folder /Volumes/x/System/Library/CoreServices --bootefi --create-snapshot


Here are some post-install terminal tweaks tested in zsh.  If you do not know what they do, don't use them:


defaults write NSGlobalDomain NSDocumentSaveNewDocumentsToCloud -bool false
defaults write com.apple.finder AppleShowAllFiles TRUE
defaults write com.apple.TextEdit RichText -int 0  
defaults write com.apple.finder _FXShowPosixPathInTitle -bool YES
sudo defaults write /.Spotlight-V100/VolumeConfiguration Exclusions -array "/Volumes"
sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist
defaults write com.apple.desktopservices DSDontWriteUSBStores -bool true
defaults write com.apple.desktopservices DSDontWriteNetworkStores -bool true


6. If you have an existing Catalina installation with third party programs they may work without modification by copying them directly from Catalina Applications folder to the Big Sur Applications folder AND copying the corresponding entries for those programs from Catalina ~/Library/Application Support to Big Sur ~/Library/Application Support.  Note that ~/Library/Application Support refers to Users/yourusername/Library/Application Support.


7. System Preferences Trackpad.prefPane does not initially appear to be working as of 11.2.


8. Automator utility can create an apple script or shell script app for Big Sur but it may fail with error message when run from the desktop if absolute paths are not specified within the script.  Test by opening the app in automator and click the step button and see if the app executes with the desired result.  Test by running the command line directly within the zsh terminal.


9.  The attached EFI with OC was modified for Skylake/520/Sunrise Point but you may find that it works for a range of models with similar Intel hardware.  Supply your own Platforminfo.  If you multi-boot with linux you can run lspci -k from terminal in linux to show your pci hardware configuration.


10.  If you desire the Open Core GUI, change the config.plist PickerMode specification from BuiltIn to External, but be aware that all icons may not be completely visible.  Change HideAuxiliary to true if you do not want to see recovery.


11.  Removing old/unwanted snapshots.

Boot into recovery mode and disable SIP: csrutil disable/csrutil authenticated-root disable.

Reboot into recovery mode if necessary.

Run the mount command to see your Big Sur partition name and disk/slice.

In terminal type:


diskutil mount /dev/diskXsY  and hit enter (where X and Y are your Big Sur disk and slice)


then type: mount -uw /Volumes/X and hit enter (where X is your Big Sur volume name)


Your Big Sur volume should now be read-write.


Run: bless --folder /Volumes/x/System/Library/CoreServices --bootefi --create-snapshot (and hit enter to generated a new snapshot)


Now you can remove old/unwanted snapshots.

diskutil apfs listSnapshots diskXsY  for a list of snapshots/uuids


delete unwanted snapshots one at a time:

diskutil apfs deleteSnapshot diskXsY -uuid (the snapshot uuid you want to delete)


12.  Change the Big Sur login background.  Boot into recovery mode with SIP/authenticated-root disabled.  


From prompt run cd /

cd into the desktop pictures folder (where X represents the name of your Big Sur install volume)
cd /Volumes/X/System/Library/Desktop\ Pictures


The default Big Sur login background in Desktop Pictures is Big Sur Graphic.heic.  You can optionally save this graphic by typing:
mv /Volumes/X/System/Library/Desktop\ Pictures/Big\ Sur\ Graphic.heic  /Volumes/X/System/Library/Desktop\ Pictures/Big\ Sur\ Graphic.heic.orig


Create a symlink to the desired login graphic....using Big Sur.heic as an example:

ln -s /Volumes/X/System/Library/Desktop\ Pictures/Big\ Sur.heic    /Volumes/X/System/Library/Desktop\ Pictures/Big\ Sur\ Graphic.heic


Run: bless --folder /Volumes/x/System/Library/CoreServices --bootefi --create-snapshot


A note regarding memory and swap.
Note if you disable swap without enough memory your machine may freeze or slow to a crawl.  The risk/performance tradeoff is up to you.


turn off swap:
sudo launchctl unload -wF /System/Library/LaunchDaemons/com.apple.dynamic_pager.plist


re-enable swap:
sudo launchctl load -wF /System/Library/LaunchDaemons/com.apple.dynamic_pager.plist


delete swap:
sudo rm /private/var/vm/swapfile*


for those who have nvram.plist:

search for swap enabled:
nvram.plist vm_compressor=4


or swap disabled:
nvram.plist vm_compressor=2


view swap status:
sysctl -a vm.compressor_mode


vram config for swap:
sudo nvram boot-args="vm_compressor=4"


for no swap:
sudo nvram boot-args="vm_compressor=2"
A note regarding disabling sleep/hibernation
check state:
sudo pmset -g | grep hibernatemode


sudo pmset -a hibernatemode 0


remove file to reclaim space:
sudo rm /private/var/vm/sleepimage
in /private/var/vm/ make a dummy:
sudo touch /private/var/vm/sleepimage


prevent write access to it:
sudo chmod 000 /private/var/vm/sleepimage
sudo chflags schg /private/var/vm/sleepimage


  • 3 weeks later...
  • Create New...