Unable to mount SD card (android), cannot install APK (1)

1. The app is installed under/mnt/sdcard by default. If your SD card is not mounted, the system will prompt you to request an SD card or damage SD card, so now you can go to this/mnt/sdcard or/sdcard (the two are in the same directory) and will not find any content.

2. Now we need to mount a partition in the sd partition to/mnt/sdcard. In this case, you can download the apk from the Internet and install it on the SD card.

3. Create a mount point in init. rc, that is, create a folder,

Create a mount point:
Mkdir/ mnt 0775 root system
Mkdir/mnt/sdcard 0000 system

Then, add the "dev_mount sdcard/mnt/sdcard auto device file path" Statement to the vfine. fstab file to enable automatic mounting when the SD card is connected. It is similar to automatic mounting on the PC:

These two statements are used to create an SD card Mount directory under the root file system and assign corresponding operation permissions and user groups, as for the/mnt/sdcard directory, it is not easy to understand why the permission assigned here is 0000. For the complete content, refer to
System/core/rootdir/init. rc. If you use adb shell, you generally do not have the write permission for the root directory. You cannot create a directory. If you do not have this directory/mnt/sdcard, you cannot mount the directory.

4. If you use the adb shell, use the remount command to mount a partition of the SD card. For details about the specific operation, see my adb command. Because it is not written into the configuration file, this is required for each power-on operation, when using shell to install apk, the installation file is placed on the PC and the adb install command is used,

If you use adb shell, it is equivalent to opening an Android device terminal on the computer. You can run commands on the device to find the device file and use the mount command to mount it. It is easier to install apk by running the adb install command. The adb tool has powerful functions. adb shell and adb install are only a small part of it.

5. Try the APK application.