I receive HFDL on Iceland, Shannon, Bolivia and Canarias system frequencies. The majority of the position reports are received without ICAO24 hex but with flight code and usually fill gaps in the oceanic coverage.

Howwever when I tried feeding these to FR24 through the PlanePlotter secondary sharing feature for a few days none of them were displayed. These were a/c that had no other coverage, not even from FAA data, so their presence was noticable. And they were not secret blocked a/c

Is it worth persisting or does FR24 require the hex?