I did mine. mainly because i was thinking about getting the lcd display for it. which would give me a good working tach. I ran into a problem when i did mine. i didn't have the 9v adapter because i bought mine used. you can't update the firmware with out it. but if u try u won't ruin the unit.
Firmware updates ensure that your unit functions as efficiently as possible and adds any new capabilities that the programmer wishes to put in place. It has no impact on your bikes performance. That is accomplished through mapping. Updating firmware merely ensures that your unit is processing data received as efficiently as possible. I wouldn't consider updating firmware critical unless the update implements fixes for known issues and you are experiencing those issues. Dynojet isn't clear on the purpose of the update but I would recommend that you update just to keep current. It's no big deal. I just did mine and it took longer to take off the seat than it did to actually perform the routine.
A quick note - you CAN update the firmware and upload maps etc. without the 9 volt adapter. I lost mine, but thanks to helpful folks here at VR, I was able to complete the task. The key is to have the engine running. Just turning the ignition on doesn't do it, start 'er up and you can do whatever you need to.