Today I ran into an issue where a Lenovo W500 (4061-3FU) would fail with error 0x80091007. Looking at the smsts.log files, found that there was an error indicating a hash mismatch between the WIM on the DP and the WIM downloaded to the local machine.
Other computers, new in the box and previously imaged, were imaging successfully. So, I suspected there was nothing wrong with the WIM itself. Received suggestions to refresh DP's with a new copy of the WIM, but I was skeptical it would solve the issue.
After trying to manually install XP SP3 on the device, I received a MEMORY_ERROR bluescreen.
Ran a hardware test on the memory using MemTest and found that the memory was defective.
So, SCCM Hash mismatch was due to defective RAM.
TechNet Forums OSD Task Sequence Fails with Error 0x80091007