Yes - but they're only using that specific 8-bit CRC to protect a 64-bit field, aren't they?!

See Dallas App Note 27: Understanding and Using Cyclic Redundancy Checks with Dallas Semiconductor iButton Products:
http://www.maxim-ic.com/appnotes..../542/ln/en

On p8:
"Because the amount of data stored in RAM can be large compared to the 8-byte ROM code, Dallas Semiconductor recommends using a 16-bit CRC value to ensure the integrity of the data, rather than the 8-bit DOW CRC used for the ROM."

The point is that Ivan has already been told all this in response to posting exactly the same question on the Keil forum.