Encountered an interesting issue doing Windows 8.1 Deployment using ConfigMgr 2012 R2. A specific model was constantly failing at the very last step in the task sequence. The smsts.log revealed a few errors with the codes 80070002 and 80072ee2, failing at random files every time from the MDT Toolkit Package.

A few examples:

DownloadFiles() failed. 80072ee2.
DownloadContentAndVerifyHash() failed. 80070002.

It seems Microsoft is aware of the issue and the current workaround is to set the following variables first in the task sequence to address the problem until it hopefully will be fixed in a coming hotfix.

SMSTSDownloadRetryCount = 5
SMSTSDownloadRetryDelay = 15

After settings these variables the deployment finish as expected.