Cannot get wifi.save() to work. Wifi settings do not survive power cycle. Cannot save code.

Can you paste the welcome screen of espruino with the version number and all that under it? Any warning about flash chip & size mismatch?

The correct stand-alone saving command is require("Wifi").save(). Perhaps you can also paste the output of require("Wifi").getDetails() right before saving.

NB: I haven't used the "combined" binary. I always flash bootloader, user1, blank, and rf defaults as individual files. Gordon wanted the combined binary to make things simpler, but I'm not convinced that there aren't ugly corner cases. For example, it doesn't clear/initialize the SDK's save areas.