Why isn it saving /etc/passwd for the next boot?
The root filesystem is being mounted in RAM. The only filesystems that you are able to write to (saving data on the SanDisk) are /os and /app. /os contains the core of the operating system, including a “root.fs” compressed image, which is what’s loaded into the ramdisk at boot time. The result of this is that no changes you make outside of the /os or /app directories will be persistent. Configuration of the device (phone number, device ID, etc.) is actually done in NVRAM and not even on the SanDisk. See the scripts in /rc for details on accessing NVRAM data. I’ll write about it here in a bit.
