I have those handhelds too. I actually have 5 in stock. It has nothing to do with the company serving tunes with the handheld device. It is a DimSport product. DimSport is the only one that really unlocks it. A code is sent to unlock the unit by the serial number. Last I checked it could be done over the internet or by email to the tuning company with a 4-6 digit code.
The problem is price last I looked into unlocking a couple of used devices. DimSport wanted $350 to send the unlock code. The unit is only $300 tuner price. Makes no sense to unlock it. Just buy a new one as the tuner service.