Help Can't update to 5.1 on Nexus 5

[Android Question]

I have a Nexus 5 that I am trying to update from 5.0 to 5.1 via a sideload ADB update. The OTA update within Android fails at about 30% so I am trying to do it manually. I downloaded the file but when it gets to about 50%, it fails every time. The phone says:

E:failed to verify whole-file signature E:signature verification failed Installation aborted

I was rooted but unrooted before attempting. I used rashr to flash back to the stock recovery as well. I tried flashing the stock 5.1 image in TWRP but all 3 components fail.