Symlnk failed in strange way on Samsung Galaxy S3 I tried to create a symlink for the external SD on a Galaxy S3 as I have done it on my HTC M8 previously. I tried with terminal emulator in command line, with Root Explorer and with Solid Explorer. It always worked and they were fully operational – but when I rebooted the device they are always lost, no track of the symlink previously created. Could someone explain, what is happening and how to correct that ? Thank you. 

I forgot, my device is GT-9300 French running Android 4.3
That very much depends on where you wanted to create the symlink. A good guess: in the root file-system? That would explain the behaviour:

Android uses an initial RAM-disk (aka "boot-image") on startup, from which it creates the rootFS (and several other things) anew each time – so changes to the root file-system don't survive a boot. That leaves you with at least two or three options:


manipulate the boot-image: only if you have the experience. Getting that wrong, and you might have to flash a fresh ROM (worst case; keeping the original, you could replace it via recovery-mode – but the try-and-err process might take a while)
use some init.d script to create the symlink on each boot: Requires your device/ROM to support the init.d system (not all do). Again, a "borked script" might screw your boot process; but you could verify your script (running it manually) before placing it into init.d, and doing so keeps the risk level very low.
Using an app-based solution: apps like tasker offer to run stuff as soon as boot is completed.