Partition Not Mounting: Smaller Size in Android Image Creation

Creating Binary Image with Various Android Partitions using dd and mountimage with losetup

This article will guide you through the process of creating a smaller Android image with various partitions using the dd and mountimage tools with losetup. The article assumes that you have a basic understanding of Linux command line and partitioning.

Prerequisites

To follow this guide, you'll need the following:

• A Linux system
• Android image file (.img)
• Partitioning tools: dd, losetup, mountimage, and mkfs

Creating Partitions

First, create a new directory for the Android image:

$ mkdir android_image
 $ cd android_image

Next, create the partitions using the dd command:

$ sudo dd if=original_image.img of=system.img bs=1M count=5000
 $ sudo dd if=original_image.img of=vendor.img bs=1M count=2000
 $ sudo dd if=original_image.img of=boot.img bs=1M count=1000

The above commands create system.img, vendor.img, and boot.img with the specified sizes.

Mounting Partitions

Use losetup to mount the images:

$ sudo losetup --find --show system.img /dev/loop0
 $ sudo losetup --find --show vendor.img /dev/loop1
 $ sudo losetup --find --show boot.img /dev/loop2

Now, format the partitions:

$ sudo mkfs.ext4 /dev/loop0
 $ sudo mkfs.ext4 /dev/loop1
 $ sudo mkfs.ext4 /dev/loop2

Mounting Partitions Correctly (Except Last One)

Mount the partitions:

$ sudo mount /dev/loop0 system_mount
 $ sudo mount /dev/loop1 vendor_mount
 $ sudo mount /dev/loop2 boot_mount

The system and vendor partitions should mount correctly. However, the userdata partition may not mount:

Mounting Userdata Partition

To mount the userdata partition, you may need to create a new partition or resize an existing one:

$ sudo fdisk /dev/sda
 # create a new userdata partition or resize an existing one
 # write changes and exit
 $ sudo mkfs.ext4 /dev/sdaX

Now, mount the userdata partition:

$ sudo mount /dev/sdaX userdata_mount

In this article, we learned how to create a smaller Android image with various partitions using dd, mountimage, and losetup. We also covered how to mount the partitions correctly, except for the userdata partition, which may require creating a new partition or resizing an existing one.