I am looking for more detail information regarding the process mentioned here:
(1) says that selecting "apply zip from sdcard" in the recovery screen will run the script and perform the mentioned commands. I suppose at this point there is no concept of android OS's root user? Is this correct? Am I allowed full access to all the files and folders in the sdcard and phone memory at this point?
The script in (1) also mentions BusyBox. I know there is an app called busybox which provides some tools, but since the android OS has not loaded up to this point, I guess the busybox in the script represents something else? Wikipedia says busybox is an old set of linux tools, so does this mean it is present by default in all android phone firmware?
The zip file containing the script in (2) contains a file called "busybox" in the zip file root (no extension, binary file) and the one in (1) doesn't. What does this mean? (1) and (2) seem to be for different phone models, but shouldn't all phones have the run_program() and delete() commands mentioned in those scripts? Would these scripts work on a different phone model? How much chance is there of the phone getting bricked? (I have stock firmware + Odin for my test phone and I am ready to format and reinstall if needed, I just want to know if there is a possibility of bricking it so badly that even Odin wouldn't recognize it)
Regardless of whether I am able to mount the sdcard/phone memory and run programs on the sdcard or not, I suppose the commands in the script such as ui_print() should work on any phone. Where can I find more commands that can be used in such a script file, and more details on how such scripts actually work? The answer can be limited to samsung phones if there are no general answers.