I'm going to give restoring a shot today--will update post as I do. ;-)

Same error.

Update: I've bricked my DTK and have spent hours today trying to restore it without success. Here's what I've done: I've tried to follow the steps outlined in "Restoring Developer Transition Kit" but have ran into several problems along the way. When I try to restore the DTK using Apple Configurator I get one of several errors: 1) When Apple Configurator connects with the device, it asks "Apple Configurator 2 would like to update Device Support for currently connected devices. Would you like to download and install this update now? ...etc." When I click "install" after a period of time (usually a couple minutes) I get an error message, "Installation failed. Can't install the software because it is not currently available from the Software Update server." I've been able to repeat this error multiple times. 2) When I try to drag the .IPSW file from the desktop of my host desktop to the device on Apple Configurator it asks me, "Do you want to install firmware version 11.0 on "Apple Controller"? (Restore/Revive/Cancel). When I choose restore, after a period of time (several minutes) I've gotten one of several error messages: A) "This System cannot be restored on this device. Failed to create new state machine for restore [com.apple.MobileDevice.MobileRestore - 0xFB1 (4017)]" B) "This System cannot be restored on this device. Failed to restore device in recovery mode, libusbrestore error:21 [com.apple.MobileDevice.MobileRestore - 0X15 (21)] C) "The System cannot be restored on this device. The operation couldn't be completed. [AMRestoreErrorDomain error 10 - Failed to handle message type StatusMsg) [AMRestoreErrorDomain - 0xA (10)] D) "They System cannot be restored on this device. Failed to copy preflight options during recovery mode restore. [com.apple.MobileDevice.MobileRestore - 0xBBC (3004)]" Note* I note that out of desperation I tried to restore my DTK while my host Mac has been running both the latest versions of Catalina, and then even installed the latest public beta of Big Sur (11.0 Beta [20A5384c]). I get similar errors messages regardless of what operating system the host Mac is running. Note* I cannot locate Apple Configurator 2.13 beta 1. However I do seem to have located a released version(Version 2.13.1 (5A35)) of this software instead. I hope that doesn't affect the process, but I'm mentioning this discrepancy in case it does have an effect. I don't know where to find an alternate version of Apple Configurator as it's not available to be downloaded (in any version) at https://developer.apple.com/download/more/ like everything else. While I am not an experienced developer, I feel that the documentation and support from Apple has not been adequate to address this situation. Thank you for any and all suggestions of how to proceed from here. I'm feeling quite stuck.