Unable to update from Big Sur beta 1(20A5299w) to Big Sur beta 9 on DTK?

I'm trying to install the latest Big Sur beta 9 on my Developer Transition Kit (DTK) so far without success after multiple attempts. Some error messages I've gotten:
  1. Software Update: When clicking on "update now," and after authentication my username, I get a consistent "download failed" message. "An error occurred while downloading the selected updates. Please check your internet connection and try again." (I've triple checked that I'm plugged into the functioning ethernet, and WiFi)

  2. I've tried to get around this by directly downloading the "Install macOS Big Sur Beta" directly from the website. (https://developer.apple.com/download/) I'm able to install the Developer Beta Access Utility successfully, and have managed to then download the installer (Install macOS Big Sur Beta), but when I try to open the file I get an error message, "This copy of the Install macOS Big Sur Beta application is damaged, and can't be used to install macOS." I've tried redownloading/restarting/etc multiple times without success.

  3. Using another computer (running Catalina) I managed to create an bootable USB drive, but I confess I'm not certain how to boot from this drive when restarting the DTK as things are different than before.

I feel a little embarrassed as a baby developer that I can't even get the beta software properly installed on my machine. If anyone can help, I'd much appreciate it. Thank you!

Best,

Tpetdoctor
I can download now(from 20A5299w), but installer crashed:

Code Block
Crashed Thread: 7 Dispatch queue: com.apple.root.user-interactive-qos
Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Note: EXC_CORPSE_NOTIFY
Application Specific Information:
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Error Domain=com.apple.LocalAuthentication Code=-1001 "Unknown credential type: '-9'" UserInfo={NSLocalizedDescription=Unknown credential type: '-9'}'
terminating with uncaught exception of type NSException
abort() called

Same issue, and the resources on website are currently not available.
Unable to update from Big Sur beta 1(20A5299w) to Big Sur beta 9 on DTK?
 
 
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