Before I rooted my FP2 and gave general writing access to the SD, I was able to give writing access card to some apps (ES File Explorer, Amaze, Open Camera, Camera ZOOM Fx) by folling this procedure:
Before I rooted my FP2 and gave general writing access to the SD, I was able to give writing access card to some apps (ES File Explorer, Amaze, Open Camera, Camera ZOOM Fx) by folling this procedure: