Startup Chord Remains after Downgrading from Big Sur to Catalina

[SRQrws]

I installed the Big Sur public beta on a 2020 Macbook Air a few days ago. The install went fine and Big Sur ran well with no significant issues other than Firefox crashing. I decided I'd had enough of a preview, though, and wanted to go back to Catalina. I deleted Macintosh HD-Data, erased Macintosh HD and downloaded Catalina via Internet Restore. I went through the usual clean install steps and everything is running fine. One curious thing has happened. The boot up chord brought back with Big Sur remains even after the erase and clean install of Catalina. I don't particularly care one way or the other, but I'm interested in knowing how that is possible and what, if anything, I neglected to do to truly downgrade back to Catalina as if Big Sur had never been installed. Any ideas? Thanks.

 

[fisherking]

you would have needed to turn off the chime while still in big sur (in system preferences>sound>sound effects); however, there's a terminal command to disable it, if you need to, just google something like "disable startup chime mac" (look for something recent)...

the startup chime happens before the OS loads, which is why the clean install of catalina didn't affect that.

 

[Superhai]

Any ideas? Thanks.

it is part of the firmware and is usually not downgraded when you install an older version of macOS.

 

[adrianlondon]

It's just a setting in nvram.

The startup chime has always worked in Catalina but defaults to off; Big Sur defaults to it being on.

To turn it on:
sudo nvram StartupMute=%00

To turn it off:
sudo nvram StartupMute=%01

 

[SRQrws]

It's just a setting in nvram.

The startup chime has always worked in Catalina but defaults to off; Big Sur defaults to it being on.

To turn it on:
sudo nvram StartupMute=%00

To turn it off:
sudo nvram StartupMute=%01

Thank you. For some reason, I missed the chime when it went away and now that it's back, I don't want it. Good to know it's easy to turn on and off.

 

[fisherking]

Thank you. For some reason, I missed the chime when it went away and now that it's back, I don't want it. Good to know it's easy to turn on and off.

haha, well now you know how to do that, and you can do it endlessly (& when u move back to big sur, it's right there in sound prefs)