There was a big discussion for Bug 5315 3 Mobile SIM card rejected @ https://bugs.maemo.org/show_bug.cgi?id=5315 regarding the disclosure of the latest firmware for testing this bug.
It's true that open source doesn't mean you must publish everything, but it does defeat the main point of open source development, which is to do with an open and involve contributions from the community.
It would be ideal to distribute future testing firmwares to trusted contributors in different continents to speed up the testing and verifying issues has been fixed, by doing so, it will significantly improve the turn-around time for the release of new firmwares, at the same time speed up and improve development.