Add exporter limitations; Remove dupe Unmanaged guide descirptions

Author: theotherjimmy

docs/tools/bootloader.md

@@ -46,3 +46,11 @@ This parameter restricts the size of the application to be at most the specified
 The start address of the current application, as computed above, is available to C and C++ as `APPLICATION_ADDR` and to the linker as `MBED_APP_START` ; The size of the current application is available as `APPLICATION_SIZE` and `MBED_APP_SIZE`. This parameter also defines `POST_APPLICATION_ADDR` and `POST_APPLICATION_SIZE` as the start address and size of the region after the application.
 
 This parameter may be used in conjunction with `target.bootloader_img` and conflicts with `target.mbed_app_start` and `target.mbed_app_size`. When used with `target.bootloader_img`, the start off the application is defined by that parameter; Otherwise, the start is the start of ROM.
+
+### Exporter limitations
+
+While the exporters can export a project using the configuration parameters above, there are some limitations. 
+
+The exporters do not interpret Mbed OS Configuration, and any changes to configuration parameters, especially boot loader parameter, require you to re-run the `mbed export` command. 
+
+Further, The exporters do not implement the post build merge used in managed boot loader builds. After exporting a project with the `target.bootloader_img` setting, you are responsible for flashing the binary mentioned in the configuration parameter. 

docs/tutorials/bootloader.md

@@ -95,16 +95,25 @@ It produces the following ROM layout:
 
 For an example showing how to create an application that uses a bootloader, see the [Mbed OS bootloader example](https://github.com/armmbed/mbed-os-example-bootloader-blinky) repository.
 
+#### Exporter limitations
+
+While the exporters can export a project using the configuration parameters above, there are some limitations. 
+
+The exporters do not interpret Mbed OS Configuration, and any changes to configuration parameters, especially boot loader parameter, require you to re-run the `mbed export` command. 
+
+Further, The exporters do not implement the post build merge used in managed boot loader builds. After exporting a project with the `target.bootloader_img` setting, you are responsible for flashing the binary mentioned in the configuration parameter. Without flashing this boot loader image, the device will not boot correctly.
+
 ### Unmanaged bootloader
 
 You want to have an unmanaged bootloader when your bootloader's requirements conflict with the requirements of the managed bootloader. You need an unmanaged bootloader when your bootloader does not come before your application in ROM or your application does not start immediately after your bootloader. Unlike a managed bootloader, an unmanaged bootloader does not automatically merge the bootloader image with the application image after building the application. We expect users of an unmanaged bootloader build to construct their own set of scripts built atop the `mbed compile` primitive to perform bootloader and application merging.
 
-An unmanaged bootloader build is a method for controlling the link location of a program within Mbed OS. There are two configuration options available for changing the link location: `target.mbed_app_start` and `target.mbed_app_size`.
+An unmanaged bootloader build is a method for controlling the link location of a program within Mbed OS. There are two configuration options available for changing the link location: `target.mbed_app_start` and `target.mbed_app_size`. Please see [Boot Loader Configuration](../tools/bootloader.md) for complete descriptions of these options.
+
 
-#### `target.mbed_app_start`
+#### Exporter limitations
 
-The configuration option `target.mbed_app_start` sets the starting address of the linker script by defining the `MBED_APP_START` macro for the linker script. You may only define this configuration option within the `target_overrides` section of an Mbed application configuration, and you may not define it for the metatarget `*`. When you do not define this configuration option, it defaults to the start of a target's ROM. This configuration option must be an address within ROM.
+While the exporters can export an Unmanaged bootloader project using, there are some limitations. 
 
-#### `target.mbed_app_size`
+The exporters do not interpret Mbed OS Configuration, and any changes to configuration parameters, especially boot loader parameter, require you to re-run the `mbed export` command. 
 
-The configuration option `target.mbed_app_size` defines the size of an application image in ROM by defining the `MBED_APP_SIZE` macro for the linker script. You may only define this configuration option on a per-target basis defined within the `target_overrides` section of an Mbed application configuration, and you may not define it for the metatarget `*`. When you do not define this configuration option, it defaults to the remaining ROM. The Mbed OS tools calculate the remaining ROM by subtracting the image's offset into ROM from the total size of ROM. Together with `target.mbed_app_start`, these configuration options define a continuous region of memory that an image may use. The tools verify that this region of memory is in ROM, but the tools do not perform any other checks for consistency or validity.
+Further, The exporters do not implement the post build merge used in managed boot loader builds. After exporting a project with the `target.mbed_app_start` setting, you are responsible for ensuring that a boot loader is present, if needed. Without flashing this boot loader image, the device will not boot correctly.