Android Marshmallow brought about some finally decent options to properly expand the storage on your phone.
As most people found out, device manufacturers have nerfed this option in some cases. My old S3 was resetting several times a day, so in buying a replacement I encountered this problem too. Admittedly my phone was a ‘cheap temporary replacement’ but still…while I am sure handset manufacturers may have genuine reasons, they are not transparent about them so the lack of a publicized and expected software feature is nothing other than frustrating.
The good news is…you can change this and you can do so without rooting.
Using adb (Android Debug Bridge – part of the Android development kit):
Connect using adb connect (with either usb or tcpip connection configured first)
In the shell type
sm list disks
which displays (in may case)
The numbers may be unique in your example, but basically ‘179,128’ is the name of my new storage.
In order to convert this to internal/adoptable storage type this, replacing the relevant numbers on the adb shell:
sm partition disk:179,128 private
Reboot your phone.
In my case, it wasn’t obvious it had worked straight away until I went to Settings->General->Storage & USB and selected what still looked like an external SD card and chose to move my apps to it, a new option. When I did this, the messages confirmed that if I wanted to turn this back to ‘portable storage’ in the future, I could. This is what I wanted to hear.
While my internal storage and SD card are still listed separately, my total storage is the sum of them both – the desired result. I also have the option on the SD to turn it back to portable.
I take no credit for the above info, I googled for it and being a developer of Android stuff (on and off) I know my way around adb thus can sift out the crap that comes up in searches. The above isn’t a tutorial…it’s just proof it works. The real reason I’ve blogged about it is so I have my own record of this madness for the next time I have to do it. Googling is quick and easy, but having your own record of what worked for you is way better than sifting through the terrible misinformation buried in stack exchange responses.
In the meantime, you can happily enjoy my record of events for the destruction of your own Android device. That’s a disclaimer there – you’re on your own in following the instructions above. Nope, I’m not responsible if you destroy your phone, sd card or data.