On Pico WebIDE Connect - Unable to retrieve board information. Connection Error?

Just to add to this...

If others hit this issue, what did you actually do to get it working?

Could re-flashing have any cause-effect on what Com port is recognized then?

On the Pico if you had a very early version of the firmware before it is possible.

Aren't COM ports dynamically assigned as needed?

For new hardware. If you have the port open in another application then the application will 'claim' that port and usually it'll be unusable by any other application until you disconnect the first one.

My contention is that all of memory is not getting erased during a flash

As I said before - on the Pico, if the flash has been successful, all flash will be erased. I'm certain of that. Saved code sits halfway between two bit of Espruino firmware, and so to update the whole firmware the saved code must be erased,

On top of that, in versions 1v96 and later there's extra code that actually checks the version of the firmware so even if you had saved code from another version it won't be loaded. If you're getting that code shown from dump() then you must have uploaded and saved that code to it at some point since the firmware update.

Is it possible that you actually have two Picos that are getting confused? That might explain some of these issues with stored code that you don't believe you uploaded.