Big Sur won't update from USB Bootable

[pavvel]

Hi,

So I have created a USB of Big Sur RC2 and tried to update from boot. I first went into recovery and turned on medium secuirty and allowed external devices.

When I went to boot from my drive I got these two messages.

Tried to update then got this...

Done a bit of research and can't find a solid answer. I am however using a usb 3.0 flash drive with the Apple official USB > UCB Type C Adapter. I don't have a flash drive with USB C inbuilt, Could this be the problem?

Thanks.

 

[pavvel]

So I went out and brought a usb-c flash drive and still the same problem.

Does anyone have any help with this?

 

[pavvel]

Anyone? Surely one of you clever clogs know about this? Can't seem to find anything out from google searching.

 

[ghostface147]

What are you trying to upgrade from? If from Catalina, you will have to install RC1 first.

 

[pavvel]

I’m on Catalina. But trying to boot from usb as clean install.

 

[CoastalOR]

Why not just wait for the official Big Sur release today, download it and make a new bootable USB?

 

[iStorm]

I'm guessing you're using a Mac with a T2 chip. These require a BridgeOS update in order to install RC2 or the final release. If this is the problem here, you'll need to be connected to WiFi in order for it to download the BridgeOS update. Another alternative might be to create the USB stick using the --downloadassets flag. I believe that should download the BridgeOS update to the USB stick.

 

[pavvel]

I will wait for the release today and try again to make a usb bootable drive. @iStorm do I just put that in the command when creating the bootable drive. I'm guessing i won't need to do this with the release version today?

 

[iStorm]

I will wait for the release today and try again to make a usb bootable drive. @iStorm do I just put that in the command when creating the bootable drive. I'm guessing i won't need to do this with the release version today?

Yes, just put that at the end of the command. The installer does not include BridgeOS, so you'll likely need to include it with the release version as well.

.../createinstallmedia --volume /Volumes/Untitled --downloadassets