I know this sounds a bit odd, but I want to disable time/date setting and update from the internet and do it manually. The reason is that I am developing an alarm clock (with various other features) based on a Pi Zero, and I want it to be usable if there is no internet connection. The development Pi is running headless, development on my desktop, so I cannot just disable the network.
I thought it would be easy, but don't really know how to do it! Ideas, suggestions?