Gaia: 14f47e5390f6fb9b0c4c841f34024870b7052cfb B-D 2013-08-23 14:27:51 Gecko: e4a2844f7941ce2c797fccdfdb03761f1f333a6a BuildID 20130823142744 Version 26.0a1 Kernel 4.3 * Symptom: In computer, user could not find and access the file system of device while USB storage is enabled and the device is plugged in any OS system computer. * Reproduce Steps 1. Open the settings app. 2. Select Media storage.(Near the bottom) 3. Turn on "USB mass storage". 4. Plug the device into: Windows, Mac or Linux. * Actual results: 1. In computer, user could not find and access the file system of device. * Expected results: 1. The device file system should be accessible on all OS systems.

Hi, The media storage in Nexus 4 is not from a individual partition so it can't be un-mounted then set to mass storage mode. Instead of that Nexus 4 used fuse technology to re-use the /data partition. This means that the media storage actually is emulated by a folder in /data partition via fuse. Please also refer to the bug as below for MTP used to this kind of device to share files between device and PC. Bug 748350 - [B2G] export files on a device to the attached desktop through MTP

> * Symptom: > In computer, user could not find and access the file system of device while > USB storage is enabled and the device is plugged in any OS system computer. > > * Reproduce Steps > 1. Open the settings app. > 2. Select Media storage.(Near the bottom) > 3. Turn on "USB mass storage". It should be the typo of "Enable USB storage" > 4. Plug the device into: Windows, Mac or Linux. > > * Actual results: > 1. In computer, user could not find and access the file system of device. > > * Expected results: > 1. The device file system should be accessible on all OS systems.