Thank you for that reference.

Will use that to continue my investigation this evening.

... Could not resist, tried already a bit ...

Looks to be more of an channel encoding issue.

The 8.5 reports that the channel is set to `lf binary` (translation & encoding).
The 9.0 seems to use `lf iso8859-1` instead, and that causes the following read to return something bonkers, and the uid handling chokes on it.

Will have to look into the internal `SetupReading` helper what is going on.

But this really has to be deferred to the evening.