If you are facing the top not secure / trunk release combination you may be able to disconnect the car battery, give it a moment to ensure all the modules lose power, reconnect and hit the trunk release button. There is a small time window where the folding top module will allow the trunk release before it completes the internal diagnostics to lock the trunk release out.
If you remove the seat base you can access the bolts that allow you to remove the rear seat backs. From there you have a couple of small holes you can get a broom handle or something similar through. It is hard to access the manual trunk release, but I have managed it with the top closed. If the top is in the trunk I think it would be impractical to reach the release.