Transfer Files to Android Enterprise Devices

In many Android deployments—especially on rugged devices—administrators need a simple and reliable way to deliver files such as configuration files, firmware updates, or resources directly to devices. Since OEM-specific file management capabilities are not consistently available across manufacturers, Silverback provides a lightweight and OEM-independent solution.

The Matrix42 Simple File Transfer application is available via the Marketplace and deployed to devices as an Enterprise App (*.apk) using Silverback. The application is designed to be simple and self-contained: it downloads files from a configured, directly accessible URL and stores them at a defined target path on the device. The file source can be hosted on the Silverback server (on-premises), in Azure, or on any other web server. Configuration is managed exclusively through Managed Configuration, allowing flexible control over the download source and destination.

To support a broad range of target paths on Android devices, the application requests the sensitive All files access permission during the first launch. This ensures compatibility with scenarios where files need to be written to locations such as /storage/emulated/0. As this is a sensitive Android permission, it cannot be granted remotely via a Device Policy Controller (DPC) such as Companion and must be approved manually on the device by the user. System or otherwise protected directories that are restricted by Android are not supported.

After installation, the application must be opened once manually to initialize background processing and grant the required permission. It then uses Android’s WorkManager to periodically (every 15 minutes) check for configuration changes. File downloads are handled by the Android DownloadManager to ensure reliable and system-integrated transfer behavior. Files are only downloaded when the configured source URL or Target Path changes, preventing unnecessary data usage. An immediate synchronization can be triggered manually using Sync now, and download completion is indicated via a system notification.

This article guides you through the complete setup and validation process, including downloading and importing the application, preparing a file hosting environment, configuring the required settings, assigning the application via tags, and verifying the deployment on a device. In addition, it demonstrates how configuration changes are applied and how the application responds to updates in real time.

System Requirements

The following requirements must be met to use the Simple File Transfer application:

• Silverback version 26.1 or later
• Companion version 26.1 or later
• Android Devices enrolled in Device Owner mode

Application Preparation

Before deploying the Simple File Transfer application, it must be downloaded from the Marketplace, imported into Silverback, and reviewed for its available configuration options. The following steps guide you through downloading the application package, importing it as an Enterprise App, and reviewing the Managed Configuration settings required for file transfer.

Download Application

• Open the Matrix42 Marketplace.
• Click Login and sign in with your credentials.
• Navigate to Add-ons by clicking the Add-ons button in the main content area.
• Locate the Simple File Transfer section.
• Click Download.
• Save the downloaded *.zip file.
• Extract the contents of the archive.

Import Application 

• Upload the extracted *.apk file by following the steps described in Add Enterprise Application.
• Before pressing save, press the Edit Managed Configuration Button once and review the managed configuration.

Review Managed Configuration

• While editing the Managed Configuration, you will see the following configuration options:
  • Download URL
  • Target Folder
  • Hide Download URL
• Press Cancel to keep the default values for now, as we will configure them at the tag level later.
• In addition, please note the following: 
  • Application configurations defined in the App Portal are applied when the application is assigned to a tag for distribution. These settings can be overridden at the tag level by clicking Edit in the Manage Config column.
• Now, finish the upload of the Simple File Transfer application by pressing save
• Proceed with File Preparation.

File Preparation

To make files available for download, they must be hosted on a web server that is directly accessible by the managed devices. In this example, the Silverback server is used as the file host. The following steps describe how to upload a file to the Silverback server, ensure proper web server configuration, and verify that the file can be accessed externally.

File Upload

• Connect to your Silverback Server.
• Navigate to your Silverback website installation directory.
  • Example: C:\inetpub\Silverback
• Create a new folder named download.
  • Example: C:\inetpub\Silverback\download
• Place the file you want to distribute in this folder.
  • Example: C:\inetpub\Silverback\download\file.zip

Review MIME Types

• Open the Internet Information Services (IIS) Manager.
• Under sites, select Silverback.
• In the middle pane, click MIME Types.
• Verify that the required file extension is listed: 
  • *.zip files are present by default
  • If you want to make *.apk files available for download, add the following MIME Type:
    • File Name Extension: .apk
    • MIME Type: application/vnd.android.package-archive

Check Download

• From a remote machine, attempt to download the file to verify accessibility.
  • Example: https://silverback.imagoverum.com/download/file.zip
• After successful verification, proceed with configuring the Simple File Transfer application.

Add and Configure Application

To distribute files to managed devices, the Simple File Transfer application must be assigned to a tag and configured accordingly. The following steps describe how to create a tag, assign the application, and define the required configuration, including the download source and target location on the device.

Create a Tag and Assign the Application

• Open the Silverback Management Console.
• Navigate to Tags and create a new Tag.
• Enter a name, enable Apps under Features, and select Android or Samsung Knox as Device Type.
• Click Save.
• Navigate to Apps and click Assign More Apps.
• Locate and select the Matrix42 Simple File Transfer application.
• Press Add Selected Apps.

Configure Application

• Click Edit.
• Adjust the app management options as required.
• Edit the Managed Configuration.
• Enter the download URL of the file you want to distribute.
  • Example: https://silverback.imagoverum.com/download/file.zip
• Enter the destination folder on the device.
  • Examples:
    • /sdcard/Download
    • /storage/emulated/0/
• Click Save twice to apply the configuration.

Tag Assignment and Installation

After configuring the application, the tag must be assigned to devices to initiate deployment. The following steps describe how to assign the tag, verify that the installation commands have been issued, and confirm that the configuration has been successfully applied on the device.

Tag Assignment

• Assign the tag to a test device or Push the tag to your already assigned devices.

Review Installation

• Navigate to Devices.
• Locate your test device and open the device overview.
• Press Actions and select Pending Commands.
• Locate the following commands: 

Review Device

• On your test device, launch Companion.
• Open the Hamburger menu in the top-left corner.
• Navigate to Profiles.
• Locate the Enterprise App Configuration Profile.
• Press the three dots next to the Profile Name.
• Press Details.
• You should see here an entry with the Application Name.

Launch the Application

After the application has been successfully deployed and configured, it must be launched on the device to initialize its functionality and grant the required permissions. The following steps describe how to start the application, approve the necessary permissions, verify that the file download is triggered correctly, and confirm that files are stored at the configured location.

Grant Permissions

• Press either Open from the Companion Enterprise App Configuration Profile or launch the Matrix42 Simple File Transfer application from the Android Launcher.
• When launching the application for the first time, the user is requested to grant the Allow access to manage all files permission.

The user is requested to grant the Allow access to manage all files permission.	The status can be reviewed under Settings > Apps >Special App access > All files access.

Overview and Logs

• After granting the permission and moving back, the Application Interface will open.
• When launching the app for the first time, users are taken to the Overview section by default. This section is divided into three categories:
  • App information (App Version, Registration Status of the Background worker)
  • Current Managed Configuration details (Source URL and Target Path)
  • Last Download information (Last Download URL and Time)
  • At the bottom of the screen, a “Sync Now” button allows users to manually trigger a synchronization.
• Before triggering a manual synchronization via “Sync Now”, switch to the Logs section to review the current application state.
  • When the app is opened for the first time, the required permission is requested (as described in the previous chapter). 
  • At the same time, a background worker is scheduled to perform automatic synchronization in 15-minute intervals.
  • However, no download is executed until the required file access permission has been granted.
  • As shown in the logs:
    • the application starts and the worker is scheduled successfully
    • the MDM configuration is checked
    • the first synchronization is skipped due to missing file access permission at the first launch
    • The log sequence represents the expected behavior during the initial application launch. As described in the introduction, the background worker operates on a 15-minute interval, meaning the first automatic synchronization attempt will only occur after this interval has passed.

File Download

• After reviewing the logs section, choose one of the following options:
  • Navigate back to Overview and press “Sync Now” to trigger an immediate download
  • Wait for 15 minutes to allow the automatic synchronization to start
• Once the download starts, it will be indicated by the Android Download Manager.
• By default, all Files will be downloaded first to the Download Folder and then moved to the destination folder, because the used Android Download Manager does not have the permissions to write in every folder on the device. Therefore, in combination with the All File access permissions, the Simple File Transfer application will let the Download Manager download the file to a path that is accessible and then move it to the corresponding target folder.
• After the download has completed, the Last Download URL and Last Download Time fields in the Overview section will be updated. 
• Additionally, the entire process can be tracked in the Logs section.

Additional Notes about File Verification 

Depending on the target path, downloaded files can be verified directly on the device using a file manager application (for example, Files by Google). For standard and user-accessible directories, such as /sdcard/Download, files are typically visible and can be accessed without restrictions. However, when files are written to locations such as /storage/emulated/0 or other less exposed paths, they may not always be visible in all file manager applications due to Android storage access limitations. In these cases, it may be necessary to verify the file transfer using Android Debug Bridge (ADB). For example, you can use the following command:

adb shell ls /storage/emulated/0/

Using ADB provides a reliable way to confirm that files have been successfully downloaded and stored at the configured location, especially in scenarios where file manager apps do not display all directories.

Change the Configuration and Review changes

After the initial deployment and successful file download, you can validate the behavior of the application by modifying the managed configuration. The following steps demonstrate how changes to the download URL and target folder are applied on the device, and how the application reacts to these updates.

Change Download URL

• After the initial download, modify the Download URL value.
• As a first step, create a copy of the file on the Server and rename it to update.zip.
  • Example: C:\inetpub\Silverback\download\update.zip
•  From a remote machine, download the new file to verify accessibility.
  • Example: https://silverback.imagoverum.com/download/update.zip
• Open the Silverback Management Console.
• Navigate to your Tag and update the Download URL in the Managed Configuration:
  • Example: https://silverback.imagoverum.com/download/update.zip

Review Changes 

• On your device, open Companion and perform a sync. 
• After the synchronization is complete, open the Matrix42 Simple File Transfer application.
  • Verify that the Source URL has been updated.
  • Once the URL has changed, you have two options 
    • Wait approximately 15 minutes for the background worker to automatically download the updated file.
    • Press Sync Now to immediately retrieve the latest configuration and trigger the download.
    • Select one of these options.
  • Open the Logs section to review the download process and debug information.

Change Target Folder

• After verifying the download, update the target folder configuration.
• Navigate to your Tag and change the Target Folder in the Managed Configuration.
  • Example: /sdcard/Documents
• On your device, open Companion and perform a sync. 
• Launch the Simple File Transfer application and verify that the Target Path has been updated.
• Depending on your previously selected option:
  • Wait approximately 15 minutes for the automatic background download, or
  • Press Sync Now to trigger an immediate update.
• Open the Logs section again to verify the transfer and review debug information.

A change in the Download URL will trigger a new download	A change in the Target Path will trigger a new download

Hide Download URLs

Before going live, it is recommended to enable the Hide Download URLs option, as transferred files may be publicly accessible or contain sensitive information.
To enable this option:

• Navigate to your tag in the management console
• Set Hide Download URL in the Managed Configuration from 0 to 1.
• On your the device, open the Companion app and perform a synchronization.
• Launch the Simple File Transfer application and verify that the Source URL and Last Download URL are now masked and only display the file name and file type.
• Next, switch to the Logs section and review that existing log entries remain unchanged and are still visible in their original form
• New download entries will be displayed with masked URLs. 

Review Application Feedback

The Simple File Transfer application provides status and diagnostic information via the Android Application Feedback mechanism. When a managed account is present on the device, this feedback is forwarded through Google services and can be accessed remotely via Silverback. This allows you to monitor the file transfer process, review execution details, and troubleshoot issues without requiring direct interaction with the device.

• Open the Silverback Management Console.
• Select Devices.
• Locate your test device and open the Device Overview.
• Click Actions and select Application Feedback.
• Locate and expand the Simple File Transfer - com.matrix42.simplefiletransfer container.
• Expand the container and review the received feedback: 

Additional Notes

• While the app is installed and configured through Silverback, the file transfer itself is executed independently on the device. The Simple File Transfer application is designed to operate primarily in the background using Android’s WorkManager. File downloads are performed using the native Android DownloadManager to ensure reliable and system-integrated transfer behavior.
• Error handling and retry behavior during file downloads are fully managed by the Android DownloadManager. This includes automatic retries in case of temporary issues such as network interruptions. The application itself has no direct control over retry logic, retry intervals, or failure handling.
• Please note that periodic background checks and download execution are subject to Android system conditions, such as battery optimization, Doze mode, and background execution limits. As a result, scheduled operations may be delayed depending on device state and system policies.
• To ensure reliable background execution, it is recommended to exclude the application from battery optimization and add it to all relevant allowlists provided by the device manufacturer (for example, via OEMConfig applications). This helps prevent the application from being restricted or paused by device-specific power management features.
• For sending logs via the Send by Mail function, an email account must be configured on the device. The default recipient is the Matrix42 Support, but this can be modified if required.
• The application supports both Light and Dark mode.
• The application is available in English, German, and French.
• It should also be noted that the required All Files Access permission cannot be granted, re-enabled, or protected from removal through the management system. Users may revoke this permission at any time via the device settings if the device is not operating in Single App Mode or Multiple App Mode. Please get in touch with your device manufacturer to check whether additional controls are supported via OEM-Config specific features.
• If the required permission is revoked, a “Grant All Files Access” button will be displayed in the Overview section 
• Additionally, each time the application is restarted, the user will be prompted again to grant the required permission. 
• As long as the permission is not granted no download will be executed and the “Sync Now” button remains disabled.