Still unable to update from block 500-600 and further, been over an hour now.
Do you have the new wallet posted on the bottom of the OP ? I used this one and had no issues with updating.
Yes, I deleted everything in the appdata/zeit folder except wallet.dat immediately after it was posted on Twitter, and I've refreshed countless times, and allowed it to update for more than an hour uninterrupted, nothing seems to break block 620 for me.