Splash Screen Message

[clegger06]

Jamf Nation,

Does anyone know if it is possible to have a message display during the pre-boot splash screen on a Mac with FV2? This would be during the "Apple" loading screen at first boot.

OR

Would it be possible to display a message during the disk unlock loading screen after you enter reds in FV2?

I am familiar with the "Security and Privacy" solution that displays during a login. I am also familiar with "Sudo" command that can be executed like so... sudo defaults write /Library/...

It looks like from the research I can find, the above questions cannot be resolved because the data we can write is on the disk, which is not loaded during a pre-boot and disk unlock process. I am just looking for confirmation if that is correct or if there is some other way. Thank you

[al_platt · Accepted solution]

You'd have to write to the recovery partition. There's stuff about this online for other things but not sure how much of your time it would take vs end result, or if it's even possible. Even if it was you'd need to make sure every machine had a customised recovery partition. Chances are this would break on every OS update.

https://jacobsalmela.com/2014/05/19/osx-customize-recovery-partition-with-your-own-apps/

https://forums.macrumors.com/threads/edit-the-recovery-partition-without-breaking-it.1598564/

[al_platt · Accepted solution]

You'd have to write to the recovery partition. There's stuff about this online for other things but not sure how much of your time it would take vs end result, or if it's even possible. Even if it was you'd need to make sure every machine had a customised recovery partition. Chances are this would break on every OS update.

https://jacobsalmela.com/2014/05/19/osx-customize-recovery-partition-with-your-own-apps/

https://forums.macrumors.com/threads/edit-the-recovery-partition-without-breaking-it.1598564/

[mm2270 · Accepted solution]

Only thing I can think of is if you set up a PolicyBanner, those display after entering your password to unlock the Mac at the FV2 screen, but before it logs into the account. Meaning, the user still must unlock the Mac, since I don't know of any way to display something at the actual Apple pre-boot screen. Only Apple can do that. But a policy banner will pop up right before the Mac logs into their account.

I personally would not mess with trying to edit the Recovery HD partition. If I'm not mistaken, the DMG that contains the Recovery HD is checksummed, so if you mess with it, it could make Recovery inoperable, which could mean breaking FV2, since it relies on that.

[michael-brodt]

As far as I'm aware, no, you cannot. That requires modification of a protected system...