Thanks to all the testing and feedback from lots of people, I have managed to reproduce and fix the scanning and reading/flashing problems with the new V2.5 firmware.
I will package the update tomorrow for download.
Almost all of the comms problems resulted from a simple change to task priority scheduling in the FlashScan operating system. The USB transmit task was not being scheduled fast enough and incoming data from the PCM was overwriting it before it could be transmitted to the PC.
I remember changing the task priorities just before releasing it while attempting to speed up BB Logging.
I should go and write out 100 lines: "I will not make changes before releasing the software - no matter how simple the change".
Regards
Paul