so far no more than 30 seconds to flash
Do you have any special settings on your USB COM port to acheive this 30 second flash? Mine used to be 180 sec, I have gotten it to 169 seconds by tweaking the com port latency speed.
That seems to be hardware dependent that your laptop or pc has. Besides latency I have not managed to get it lower without getting a new hardware for USB.
Would be interesting to know what kind of computer mike is runnig. In the local dyno shop there is an extra usb2 card and exteral usb hub and we get 30sec flash times. On my laptop its the same 169s. This speed difference is something not yet fully understood and requires more investigation. If you use an old style programmer for serial port only then you get 48sec, but loose the data monitoring capability. Been in tourch with FTDI, but they can not help it much either.