In view of the unique circumstances on the island of Ireland, flexible and imaginative solutions will be required to avoid a hard border...
...This must be achieved in a way which ensures that Ireland's place within the Internal Market and Customs Union is unaffected.
To be clear, this is a quote from the document. (Though I agree with all of it, including the last bit.)
Excluding physical infrastructure including hi-tech scanning equipment etc. rules out Norway-Sweden and US-Canada as acceptable options
and indeed they were never even remotely acceptable to the Irish side of this particular debate, as has long been obvious.