Big Sur change user login background

[Humanate]

On Catalina it was quite straightforward to change the user login background but not with Big Sur due to System/Library now being Read Only

 

Can anyone tell me how I might do this? I have googled but just ended up head scratching

[HenryV]

You boot into the recovery mode, open terminal, with SIP/authenticated-root disabled, and run mount command to see your Big Sur volume name.  Be sure not to confuse this with the Big Sur data volume using the same name with a dash and the word data.

 

The Big Sur volume should indicate 'sealed'.

 

In terminal run:  mount -uw  /  /dev/diskXsY

 

X=your Big Sur disk from 'diskutil list'

Y=your Big Sur disk slice

 

Now the Big Sur volume should be writable.

 

type cd / at the prompt, hit enter

type ls, hit enter, to see the directory listing.

 

Next type cd /Volumes/X/System/Library/Desktop\ Pictures where X is the name of your Big Sur volume.

 

Now you should be in System/Library/Desktop\ Pictures where the stock greeter graphic is Big Sur Graphic.heic. 

 

Type mv /Volumes/X/System/Library/Desktop\ Pictures/Big\ Sur\ Graphic.heic /Volumes/X/System/Library/Desktop\ Pictures/Big\ Sur\ Graphic.heic.orig  to save the original.

 

Next you can create a symlink to another graphic using terminal by typing:

 

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

 

Remember that X stands for your Big Sur volume name

 

This will create a link to the Big Sur coastline picture with the bridge in the foreground.

 

cd back to the root of the console and type;

 

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

 

Remember that X stands for your Big Sur volume name.

 

Hit enter and wait for the snapshot to update.

 

Make sure csrutil status shows disabled.

Make sure csrutil authenticated-root status shows disabled.

 

Reboot and if you have not made any errors your greeter graphic should be changed.

 

 

Edited November 18, 2020 by HenryV
correct technical error

[Humanate]

Henry, thank you so much for the detailed instructions. I had read some posts in other places on this trying to explain the approach but they were not easy to understand

 

I really appreciate you taking the time to make so clear for me. I will do this tonight when I get home and report back

[Humanate]

Henry, thank you so much for the detailed instructions. I had read some posts in other places on this trying to explain the approach but they were not easy to understand

 

I really appreciate you taking the time to make so clear for me. I will do this tonight when I get home and report back

[Humanate]

On 11/16/2020 at 7:52 PM, HenryV said:

You boot into the recovery mode, open terminal, with SIP/authenticated-root disabled, and run mount command to see your Big Sur volume name.  Be sure not to confuse this with the Big Sur data volume using the same name with a dash and the word data.

 

The Big Sur volume should indicate 'sealed'.

 

In terminal run:  mount -uw  /  /dev/diskXsY

 

X=your Big Sur disk from 'diskutil list'

Y=your Big Sur disk slice

 

Now the Big Sur volume should be writable.

 

type cd / at the prompt, hit enter

type ls, hit enter, to see the directory listing.

 

Next type cd /Volumes/X/System/Library/Desktop\ Pictures where X is the name of your Big Sur volume.

 

Now you should be in System/Library/Desktop\ Pictures where the stock greeter graphic is Big Sur Graphic.heic. 

 

Type mv /Volumes/X/System/Library/Desktop\ Pictures/Big\ Sur\ Graphic.heic /Volumes/X/System/Library/Desktop\ Pictures/Big\ Sur\ Graphic.heic.orig  to save the original.

 

Next you can create a symlink to another graphic using terminal by typing:

 

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

 

Remember that X stands for your Big Sur volume name

 

This will create a link to the Big Sur coastline picture with the bridge in the foreground.

 

cd back to the root of the console and type;

 

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

 

Remember that X stands for your Big Sur volume name.

 

Hit enter and wait for the snapshot to update.

 

Make sure csrutil status shows disabled.

Make sure csrutil authenticated-root status shows disabled.

 

Reboot and if you have not made any errors your greeter graphic should be changed.

 

 

Failed at the first hurdle. I suck, apologies, hate terminal!

 

Here is a pic of diskutil list when booted into Big Sur, I know I will be in Recovery but easier to take screen shot for me. Above you say "Y=your Big Sur disk slice" - So in the example below, would this be disk2s1 or disk2s2 or is it neither of those?

 

 

I tried both disk2s1 and disk2s2 on separate attempts and then typed "ls" and could see the directory listing. Then I typed: "cd /Volumes/macOS Big Sur/System/Library/Desktop\ Pictures" and I would get "no such file or directory" or similar message.

 

I'm sure I am making rookie mistake/s and apologise for my ignorance, still learning all the time!