Long story short,

I did a fresh OS install on Drive 0.... which has... strike that, had, my BTC wallet on it.

I managed to stop the install, but the damage was already done.  I recovered wallet.dat with EaseUS but the .dat is a garbled mess that pywallet can't read.
However, I know the BTC addresses associated with the wallet and the passphrase. Can I regain access?

Thanks for any assistance.