Dell XPS 15 BIOS Upgrade - Reboot asking for Bitlocker Recovery Key

I have a Dell XPS 15 9550, and after a recent BIOS upgrade, it seems to have lost the PIN, and is asking me to enter a BitLocker recovery key, which so far at least, I've been unable to find.  So does anyone know how to:

1. Reenter the PIN so that the system boots normally (TPM/UEFI/etc.)?
2. If that is not possible, re-install Windows 10?

The system was upgraded right after purchase from Windows 10 Home to Pro, otherwise is pretty stock.  

When I go through the various recovery options to Troubleshoot:

• Reset this PC:  It asks again for the recovery key (which I do not have)
• Advanced > System Restore:  Same (recovery key which I do not have)

I realize that the without the Bitlocker recovery key, that the data may be all lost, but what I would like to do is get the system running again, at least to the point I can re-install Windows.  I have the PIN of course, but cannot seem to get to the point where the system prompts for it, it is stuck on the Bitlocker key, which I cannot find.

Suggestions?