Edit: it went away after I finshed the t2linux setup
Probably because the sound is hardcoded into the firmware, because Apple, and fuck you
They’ve been doing this for decades. The Mac boot sound has been hard coded since Macs were a thing.
SGI used to do this with their Irix workstations.
I’m amazed at what they decide to waste their time on just because fuck you
The ghost of Steve Jobs is in the machine.
macOS installs a recovery partition and hides it from you so you can always restore it.
I think the firmware boots you into a macOS mode so you can always recover your macOS system, but when you finished installation Linux may have nuked it.
I’m not an expert though, I’ve just been using Mac’s for 15+ years and have had to reformat several over the years.
I’ve never installed Linux as the primary OS before.