This must work on all Android One ROMs including Marshmallow.
This won't work if SD Card (Memory Card) is used as Internal Storage from Marshmallow 6.0, since it's formatted as an EXT4 partition and encrypted.
[APP][ROOT] Universal USB Mass Storage Mode Enabler
Select the 'Enable UMS (Hard Method)' in that app..
Hit the Thanks Button if it worked for you
Old Method for Android One Devices ( I just kept this for no reason, not recommended):
Old Method(Not Recommended):
NOTE: This is only for Sprout 4 devices ( I mean Android One devices with 4 GB Internal ROM)
Take a complete backup of phone before doing this. I'm not responsible for boot loops.
Okay, I tweaked the USB configs to Enable USB Mass Storage Mode and other tweaks to mount /system, /data, /oem and /cache partitions.
For Sprout8 phones , give me the boot.img of your phone to make one for you
If it doesn't work, flash your old boot.img which will be at /data/original_boot.img to revive your phone incase of boot loop.
And post the boot.img of your ROM here to create one for that ROM.
INSTRUCTIONS for Mass Storage Mode:
1. Set SE Linux mode to Permissive.
2. Download and flash this from custom recovery:
Lollipop: 5.1.x Sprout4 UMS Enable.zip (tested on 5.1 & 5.1.1)
Universal (for mostly all ROMs): UMS.zip (Credits: Created and tested by @out386)
KitKat: 4.4.4 Sprout4 UMS Enable.zip (Not tested)
Marshmallow: 6.0 Sprout4 UMS Enable.zip (Will be added soon)
3. Connect the phone to computer or TV or DVD or whatever.
4. (After flashing is done properly,) Install this app: UMS Enabler and press "Enable UMS"
That's It! Mass Storage will be enabled!
INSTRUCTIONS for Mounting Other partitions to Computer:
1. (This will work flawlessly in Linux OS like Ubuntu.)
For Windows, you must know how to mount or read EXT4 partitions.
I use Ext2Fsd. It works smooth
2. After disabling SELinux Enforcement, flashing the updated zip (above) and installing that app, open it.
3. Click 'Advanced' Button.
4. Then mount whatever you want from there.
(I just did this for no reason . Be careful while working with those partitions.
Do not modify or delete the files in it unless you know what you're doing.
And properly eject (umount) the partition in PC before unplugging to avoid issues)
You can use the /data partition as Internal Storage if you wish )
Plz report me if it's not working, or if you have any issues.