20 Flashing Images Using bmaptool

A fast and easy way to flash an image to a bootable device is to use bmaptool, which is integrated into the OpenEmbedded build system. bmaptool is a generic tool that creates a file’s block map (bmap) and then uses that map to copy the file. As compared to traditional tools such as dd or cp, bmaptool can copy (or flash) large files like raw system image files much faster.

Note

If you are using Ubuntu or Debian distributions, you can install the bmap-tools package using the following command and then use the tool without specifying PATH even from the root account:
```
$ sudo apt install bmap-tools
```
If you are unable to install the bmap-tools package, you will need to build bmaptool before using it. Use the following command:
```
$ bitbake bmaptool-native -caddto_recipe_sysroot
```

Following, is an example that shows how to flash a Wic image. Realize that while this example uses a Wic image, you can use bmaptool to flash any type of image. Use these steps to flash an image using bmaptool:

Update your local.conf File: You need to have the following set in your local.conf file before building your image:
```
IMAGE_FSTYPES += "wic wic.bmap"
```
Get Your Image: Either have your image ready (pre-built with the IMAGE_FSTYPES setting previously mentioned) or take the step to build the image:
```
$ bitbake image
```
Flash the Device: Flash the device with the image by using bmaptool depending on your particular setup. The following commands assume the image resides in the Build Directory’s deploy/images/ area:
- If you installed the package for bmaptool, you can directly run:
```
$ sudo bmaptool copy build-directory/tmp/deploy/images/machine/image.wic /dev/sdX
```
- Otherwise, if you built bmaptool with BitBake, run:
```
$ sudo chmod a+w /dev/sdX       # get write access to the media, needed only once after booting
$ oe-run-native bmaptool-native bmaptool copy build-directory/tmp/deploy/images/machine/image.wic /dev/sdX
```

For help on the bmaptool command, use the following command:

$ bmaptool --help