I recently purchased several Vertex VX4000 VHF 148-174MHz (c) models and they work great. The eBayer I got them from modified the programming file with a hex editor and it allowed the units to drop down into the ham bands. He indicated that found the instructions here. All I have is a file that I can never lose if I want 2 meter operation

I'd love to know how to do this on my own. He told me to look in the file and I'd see where to make the change. Um, nope and I've been a software developer for 30 years and know how to use a hex editor
I also have a VX4000 VHF Low Band model that covers 37-50MHz and I wonder if the same trick can be used to get it up to 6 meters. I'd like to add a 6 meter input to my 2m/440 repeater or even build a 6 meter repeater at 51.700(-) -- so close.
I'd appreciate any input in this.
Bob - AF6D