Let's say I want to run some app requiring root access on my HTC Droid DNA (2.06 stock firmware, 4.1 Android, NOT broken, meaning it's S-ON).
My (somewhat naive) understanding of S-ON/S-OFF is that it write-protects the ROM, and thus makes writing anything into it impossible (such as whatever changes are needed to install root that persists from boot to boot).
The question is, is there a way to obtain temporary root without breaking S-ON, such that it only persists till next boot? (with the understanding that any changes to filesystem made by the need-root application that would have been saved into protected parts of the filesystem would ALSO be lost after reboot).
P.S. Please note that the question is about technical detail about rooting - asking me to clarify which app I need to run to help me do the same task without rooting is entirely off-topic.