Big Sur Beta 4 on External USB Drive Installation Stuck

I'm trying to install the Big Sur developer beta onto an external USB drive as a fresh install.

I can run the installer, select the drive, and start the installation process. It goes into the black screen with the Apple logo showing how many minutes. After 6 hours (!), it reboots a few times, then gets stuck with the progress bar at about half way through.

At that point, I've tried rebooting into Recovery mode and running Disk Utility First Aid on the USB drive, which fixes one issue. When I reboot again, the progress bar goes to complete, but it never boots into Big Sur. Also tried booting into Safe Mode without luck.

I'm on a MacBook 13" Early 2015 Retina. I've tried this using the Beta 2, 3, and 4 installers.

Any help or thoughts would be greatly appreciated.

Thanks!
Chris
Same even with the official.
Big Sur Beta 4 on External USB Drive Installation Stuck
 
 
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