It certainly looks like, Google has disabled USB Mass storage option for most recent Android versions as you probably have noticed,
do not allow you to mount SD Card / storage partition as USB Mass Storage (UMS)
when plugging it to a computer.
Given that you are rooted, you can try the following resoltuions:
- Using terminal to mount mass storage
setprop persist.sys.usb.config mass_storage,adb
If you want to go back to MTP, open terminal emulator and enter:
setprop persist.sys.usb.config mtp,adb
setprop sys.usb.config mtp,adb
- Activate auto-mount when USB debugging is enabled.
As previously mentioned, when USB debugging is enabled the sd card will automatically mount when connected to the computer provided the drivers were installed correctly.
Thus you will not get persistent notifications about sd card monting
- Using QtADB
QtADB is a full-featured tool (designed for windows )and has a plethora of features to manage your droid. Some of these include:
File manager (copying files and dirs between phone and computer, delete , creation of dirs)
App manager (installing, removing, creating backs ups etc)
Shell and more..
The essence of this is that it alows mounting of external sd card to a computer without giving annoying notifications. Check here for more info: QtADB
- Using USB MASS STORAGE Enabler (root)
This is one of the few apps offering to restore the lost Universal Mass Storage (UMS) option.
After downloading the tool ,connect your device using USB cable to your computer.
Open the ‘UMS Enabler’ app and press ‘Enable Mass Storage’. Remember, give the app root access if it asks.
At this point, you might get various messages by the app, for instance, there a message asking you to set SELinux – a Linux module Android uses to make it more secure – to permissive state; this is required for the app to run properly
- Any way to get USB Mass Storage instead of MTP?
- How To Mount Android Device As USB Mass Storage (UMS)?
- QtADB for android