IMG Environment Variables (Compact 2013)

3/26/2014

IMG environment variables control image configuration options. You can change IMG variables from the properties page for your OS design project. If you change an IMG environment variable, you can rebuild just the run-time image instead of rebuilding your entire OS design. For more information about how to change IMG variables and rebuild the run-time image, see Procedures for IMG environment variables.

There are two categories of IMG environment variables.

• IMG variables. These IMG variables add modules to your run-time image or change the image configuration.
• IMGNO variables. These IMG variables exclude modules from your run-time image that are on by default. To exclude the module from your final run-time image, set the IMGNO variable to 1.

The tables in the following sections describe the IMG and IMGNO variables.

IMG environment variables

The following table shows IMG environment variables. Many of these variables control debugging options that should not be enabled in a shipped product.

Environment variable	Description
IMGASLRENABLE	Enables Address Space Layout Randomization (ASLR), a computer security technique in which the positions of key data areas are rearranged randomly within the address space for a process.
IMGAUTH	Enables run-time images to be keyed to a specific device. This variable makes sure that the images are flashed only on the selected device. When the device starts, it validates the run-time image signature by making sure that the signature matches the hardware device ID.
IMGAUTOFLUSH	Configures CeLog to automatically flush events to a specified directory. Note: Do not include CeLog on a shipping device because the logging that CeLog performs can reduce system performance. Also, omitting CeLog reduces the attack surface through which a malicious user could try to compromise the system.
IMGCELOGENABLE	Adds CELog.dll to the run-time image and initializes event logging when the run-time image starts. Note: Do not include CeLog on a shipping device because the logging that CeLog performs can reduce system performance. Also, omitting CeLog reduces the attack surface through which a malicious user could try to compromise the system.
IMGEBOOT	Reserves space for the boot loader in ROM.
IMGFLASH	This environment variable is available to board support package (BSP) vendors for custom implementation.
IMGHDSTUB	Adds OS awareness for hardware-assisted debugging.
IMGMULTIXIP	Controls the BIB selections that allow componentization of BIN files. The exact implementation of this variable is BSP-specific.
IMGNXSUPPORT	Adds OS support for ARM’s “No eXecute” functionality.
IMGOSCAPTURE	Adds OSCapture.exe to the run-time image. It starts buffering events in RAM when the run-time image starts.
IMGPROFILER	Enables Monte Carlo kernel profiling in the run-time image. For more information, see Running the Kernel Profiler in Monte Carlo Mode. Because the profiler takes up memory and reduces performance, you will usually turn this option off in shipping devices.
IMGRAMx variables	This set of IMG variables configure the run-time image to use a designated amount of RAM. On some platforms, the run-time image will automatically resize based on the amount of RAM available. Use one of the IMGRAM variables to specify the size of the run-time image: IMGRAM16 = 16 MB IMGRAM32 = 32 MB IMGRAM64 = 64 MB IMGRAM128 = 128 MB IMGRAM256 = 256 MB IMGRAM512 = 512 MB
IMGRILCOM1	Configures the RIL driver to open COM1 instead of COM2 for the AT command/response port.
IMGSIGN	Includes the signature extension block in the ROM header.
IMGTINYFSRAM	Sets FSRAMPERCENT that reduces the RAM allocated for the file system. For more information, see Binary Image Builder (.bib) File and FSRAMPERCENT.
IMGTRUSTROMONLY	Sets ROMFLAGS that configures the run-time image to trust only modules in ROM. For more information, see Binary Image Builder (.bib) File and ROMFLAGS.
IMGDUALPORTRIL	Configures the RIL driver to use a MUX driver instead of a raw serial driver.

IMGNO Variables

The following table shows the IMGNO environment variables. Set these variables to 1 to exclude “always on” features from your run-time image.

Procedures for IMG environment variables

Use the following procedures to change the IMG variables and rebuild the run-time image. You can rebuild the run-time image either from within Platform Builder or from the command line.

To change an IMG environment variable

1. Open your OS design in Visual Studio.

2. On the Project menu, select Properties to open the Property Pages dialog box.

3. In the Configuration drop-down list box, select the build configuration you want to modify. If this OS design supports more than one BSP, use the Platform drop-down list box to select the BSP you want to change.

4. On the left of the Property Pages dialog box, expand Configuration Properties, and then select Build Options.

5. Select the IMG environment variable you want to change, use the drop-down arrow on the right to select the new value, and then click OK.

To rebuild the run-time image from Platform Builder

1. Open your OS design in Visual Studio.

2. On the Build menu, select Make Run-time Image.

To rebuild the run-time image from the command line

1. Open a command window.

2. Change the command path to the flat release folder for the OS design that you want to build.

   Tip

   If you are not certain where the flat release folder is, open Platform Builder. On the Build menu, select Open Release Directory in Build Window to open a command window with the path set to the release folder.

3. At the command prompt, type makeimg.exe. For more information about Makeimg.exe, see Make Binary Image Tool (Makeimg.exe).

See Also

Reference

BSP Environment Variables
PRJ Environment Variables
Miscellaneous Environment Variables

Other Resources

Environment Variables