Initial Login Screen Wallpaper on M1 Macs

[ralphthemagi]

I have seen a number of threads about this, but they devolve into a bunch of "solutions" for tangential bugs and/or issues.

What I am trying to figure out is whether or not the Initial Login Screen (I am talking about the INITIAL login screen after a cold boot, NOT the Lock Screen) wallpaper on M1 Macs (the MBP specifically) is changeable or is essentially fixed. I'm trying to figure out if this is a bug or working as expected.

I have two configurations:

1. A 2016 Intel MBP (Silver) ruinning 12.2
2. A 2021 Apple MPB (Silver) running 12.2

Both have multiple users enabled. Both are set to "List of users" for login. Both have FileVault enabled.

• On the 2016 Intel MBP the Initial Login Screen has the desktop wallpaper as the purple/blue/pink "Monterey Graphic".
• On the 2021 Apple MBP the Initial Login Screen has the desktop wallpaper as Chroma Blue.
• After you select a user and login the desktop wallpaper then changes to whatever the desktop wallpaper is for that user. This will be reflected on the Lock Screen. However, if the user fully signs out, the system then defaults back to the Initial Login Screen as noted above.

For the Apple MPB the Chroma Blue desktop on the Initial Login Screen appears to be unchangeable. I also noticed that the UIs between the two are actually different when placed side by side. On the Intel MBP the selected user has a transparent rounded rectangle around the user profile picture and name. On the Apple MBP the selected user has a white ring around the user profile picture. Very odd, but leads me to believe that the software that runs pre-login is actually different between Intel and Apple builds. I have heard some people suggest that it is actually fixed in firmware or in an inaccessible hidden volume, and that the Silver MBPs default to Chroma Blue and the Space Gray MBPs default to Chroma Red. Weird if true, but that's essentially what I am trying to confirm.

Does anyone have a new Intel MacBook Pro that displays anything OTHER than Chroma Blue/Chroma Red as the Initial Login Screen desktop wallpaper? If so, do you FileVault enabled and/or multiple users setup?

And yes, I realize this is totally asinine, but anyway here we are. But I hate not knowing why something is the way it is.

 

[BigBlur]

I have an Intel MacBook, so can't really confirm anything, but I wouldn't be surprised if they are making the initial login screen wallpaper on the new Macs behave similar to how the default wallpaper works on iPhones and iPads.

When a new iPhone or iPad is released, each model and color have their own "device specific" default wallpaper. When the next major iOS/iPadOS version is installed, then it uses the OS's default wallpaper.

Based on what you've said, and what I've read elsewhere, it sounds like this is what's going on here. It's likely your 2021 MBP will use the device specific wallpaper while macOS 12 is installed (since that's the version it was shipped with), and then would switch to using the OS's default wallpaper when it's upgraded to macOS 13.

 

[ralphthemagi]

I have an Intel MacBook, so can't really confirm anything, but I wouldn't be surprised if they are making the initial login screen wallpaper on the new Macs behave similar to how the default wallpaper works on iPhones and iPads.

When a new iPhone or iPad is released, each model and color have their own "device specific" default wallpaper. When the next major iOS/iPadOS version is installed, then it uses the OS's default wallpaper.

Based on what you've said, and what I've read elsewhere, it sounds like this is what's going on here. It's likely your 2021 MBP will use the device specific wallpaper while macOS 12 is installed (since that's the version it was shipped with), and then would switch to using the OS's default wallpaper when it's upgraded to macOS 13.

Interesting. I had not noticed this. That would actually explain it, from a design standpoint.

What is interesting is that someone noticed that the difference between Chroma Blue and Chroma Red maps to Silver / Space Gray respectively—and that this is actually consistent with their marketing materials. When a Silver is shown, it's Chroma Blue and when a Space Gray is shown it's Chroma Red. A bizarre attention to detail, but one that is actually kind of annoying.

 

[ralphthemagi]

I've been looking into this quite a bit. Turns out, this is not a bug. I'm not sure if it's all M1 Macs or just the new M1 MBPs, but I can at least now confirm that all M1 MBPs show Chroma Red/Chrome Blue by design.

A LOT has changed in macOS since the Intel Catalina/Pre-Catalina days and M1/Monterey. I did not realize that the macOS I knew is long gone. I learned quite a bit by reading through the articles here: https://eclecticlight.co/m1-macs/ The author, Howard Oakley, has done an absolutely incredible job documenting the changes that have been made to macOS in the last 4-5 years.

These wallpapers are either part of the SSV (Sealed Snapshot Volume) or part of the new iBoot on M1 Macs—I'm not sure which. In any event they are (practically speaking) unchangeable. They are part of the OS that is signed and distributed by Apple and can be (and likely are) model number specific. I say that because that's how it's been on iOS for a while, it's just less noticeable—iOS default wallpapers are different based on model.

The reason behind locking down this wallpaper is security. All parts of the system that load before login are designed to be signed and bit-for-bit unmodified by Apple. How/why Apple allows the user profile icons to load I'm not sure. If you notice, they are extremely low resolution before you login. If I had to guess what Apple is doing here is saying that user profile photos are okay to load because they are heavily compressed, so they may feel there isn't a practical way to include a malicious payload into a user profile picture that is only a few kilobytes, so it is not deemed a security risk. A high resolution desktop wallpaper, on the other hand, could be a security risk so it is not allowed; and the alternative—compressing a desktop wallpaper to a few kilobytes would be quite ugly. How and why they decided to make it Chroma Red/Chrome Blue I have no idea, but it is what it is.

One final note: it might be technically possible to change this, but to do so you would have to turn off almost all of the security features and really dig around to find out where this screen is. You'd also have to enable Permissive Security mode and turn off SIP. The wallpaper would also be reset with any future macOS update. It may cause all sorts of other unintended problems, since system integrity will no longer be bit-for-bit verified.

 

[HMI]

Thank you. I was looking for this.

I have chroma red, which I absolutely hate - My least favorite color by a long shot.
I wish they could at least let you choose between a few different designs and colors that are baked into the OS, so you’re not pissed off every time you turn on your (expensive) MBP.

At least let me change from chroma red to chroma blue dark!

There must be a way to make that work!

Hell, if I can inscribe a Memoji on an AirPods case before I buy it, I should be able to select a blue wallpaper design on Apple‘s website before I buy my MBP, just so that I don’t have to stare at that ugly red one every day for the next 5 years.

 

[HMI]

I guess whatever changes they made to Ventura fix this?

All I did was select the default dynamic orange flower wallpaper for the first desktop of my Spaces, and when I shutdown/reboot, I see the orange flower login screen instead of the old red design screen from Monterey.

I'm not the biggest fan of flowers as my wallpaper, but I'll take it to avoid the red login screen....haven't tried any others yet, but I will later.

 

[BigBlur]

I guess whatever changes they made to Ventura fix this?

All I did was select the default dynamic orange flower wallpaper for the first desktop of my Spaces, and when I shutdown/reboot, I see the orange flower login screen instead of the old red design screen from Monterey.

I'm not the biggest fan of flowers as my wallpaper, but I'll take it to avoid the red login screen....haven't tried any others yet, but I will later.

I think this goes back to my post above. Devices use their device branded wallpaper out of the box; but once it's upgraded to the next major OS version, it'll start using the OS's default wallpaper for the login screen. Selecting it as your desktop background likely had nothing to do with it.

 

[HMI]

Ok. Thanks.

 

[ralphthemagi]

I guess whatever changes they made to Ventura fix this?

All I did was select the default dynamic orange flower wallpaper for the first desktop of my Spaces, and when I shutdown/reboot, I see the orange flower login screen instead of the old red design screen from Monterey.

I'm not the biggest fan of flowers as my wallpaper, but I'll take it to avoid the red login screen....haven't tried any others yet, but I will later.

Nothing was fixed because it’s not really a bug. Many of the macOS screens now load from a sealed snapshot which can’t be changed. The orange flower is now the default screen for initial login for all Macs. Oddly, it seems like Chroma Blue/Red still appear after initial login, but if you log out of all users. So you will still see it from time to time, as that screen is also part of a sealed snapshot I believe.

There are three states:
1) Initial login
2) Login Screen (change users or log out after initial login)
3) Lock Screen

As far as I can tell, #3 is the only screen that’s user changeable. #1 is what loads before the disk has been decrypted. #2 is some kind of in-between state where the disk has been decrypted, but you aren't operating in any user space.

 

[star-affinity]

What seems a bit incoherent to me is that even after having logged into a macOS account, putting the Mac to sleep and locking it, upon wake it most of the time show the custom background as expected, but at times (pretty rare but it happens) it displays the Ventura background for some reason. This just happened to me to day and I then tried to put the computer to sleep again (pressed the touch-ID/power button) and immediately woke it up again upon which it switch to my custom background. 🤷‍♂️