> If these were esims they would be much harder to detect or remove?

It's not clear in the article how exactly they discovered it, but by the text that mentions it, I do get the impression they just came across the SIM ports/cards themselves:

> internal tests at a secure facility found Romanian SIM cards inside the buses

But it could also have been that they put the entire bus in a giant Faraday cage (or similar) and tried to see if it emits anything. If they did that, then eSIM or SIM wouldn't have matter, nor where on the bus it was, they'd eventually see it. But if they just physically came across it, then maybe eSIMs would allow them to place them in less accessible areas. But then maybe that wouldn't matter anyways, if the SIM cards are permanently attached anyways.

Bottom line, hopefully wouldn't have made a difference.

A local group of security people have been running a weekend project they call Project Lion Cage where they take Chinese cars into a local mine with spectrum analyzers etc. to watch where they send data and so on. This is how the bus was evaluated as well. Tor Indstøy has quite a few posts on his LinkedIn page talking about the work and what they have found.

Press release (Norwegian): https://www.mynewsdesk.com/no/ruter/pressreleases/ruter-tar-...

"But it could also have been that they put the entire bus in a giant Faraday cage"

And that's what they did. If that was necessary for the conclusions is not said in the article. Only that the remote access could

  - Update software (well, that's pretty common)  
  - Diagnosis (ditto), and 
  - Manage the control system for battery and power supply.