A follow-up post This may be a bit techy After having a play and figuring what does what - the Mainflash (1MB) is the core software for the cluster and the Workflash contains the settings by pure accident i flashed a blank Workflash this defaulted the cluster but was unable to write the mileage we now know the mileage is stored in the Workflash so if we compare a pair of files with different mileages we can see what changes are made to the binary with ExamDiff pro we can now