Hi; @hearwell
Good point. No, the lock is not only about the hearing aid. It's mainly about the fitting software recognizing that model hearing aid.
Once your specific installation of (Oticon Genie 2 fitting software) has the ability to recognize Oticon Engage hearing aids, then that specific installation of Genie 2 will continue to recognize all Oticon Engage hearing aids. Unless something drastic like a crash that requires reinstalling Windows, or some other drastic event occurs.
Whew! That took a while to word the (Unlocking Locked Hearing Aids) PDF file correctly as explanation for why it's a software lock and not a hardware lock. Give it another look when you get time.
Snip from DIY School PDF File named (Unlocking Locked Hearing Aids) which has instructions +Plus the unlock code (which is not a secret and has already been revealed in multiple places). The instructions and code will assist in unlocking the NHS Oticon Engage aka Oticon Opn 2. Though, as usual you should read the actual DIY School (v2.0) PDF file for the latest updates (if any). It's easy to find DIY School (v2.0), just click any PVC Avatar. Hint click twice.
Genie 2 is for Newer/Current hearing including the Oticon Opn 2 (a.k.a. Oticon Engage)
The NHS Oticon Engage is equivalent to Oticon Opn 2 hearing aids and is locked. Please read a DIY School Hearing Aids PDF file named (Unlocking ReBranded Hearing Aids) for how to unlock NHS Oticon Engage hearing aids
Wireless fitting using a Noahlink Wireless hearing aid programming device is available for the Oticon Engage and seems the more-modern choice for a hearing aid programming device. Hi Pro + CS44 cables + flexstrips is also available. But this type of cabled connection is going obsolete.
Legacy Oticon BTE; However, it is not listed as a model in Oticon's Legacy fitting software (Genie 2017.1) even when you click the model overflow button tagged as "More"-or-"MORE".
So I don't know how you will be able to program it without the fitting software?
If you had the correct hearing aid fitting software, then you would also need a hearing aid programming device (Hi Pro or mini Pro), plus standard CS44 cables, plus Boots that fit onto the back end of the K50 (similar to this Oticon Chili model);