Resolve documentation pointing to wrong SDK

In the documentation we should just recommend that people use cmake to
pull in the correct version of the SDK.

doc/guide/building-examples.md

@@ -27,55 +27,37 @@ You can drag and drop this UF2 file into the `SONATA` drive to program the firmw
 
 ## Baremetal examples
 
-This is only for advanced users.
+This is **only for advanced users**.
 If you want to build the baremetal examples in the Sonata repo you can follow these instructions.
 
 ### Additional Toolchain Setup
 
-Besides the compiler, there are a few more features the example code depends on:
+Besides the compiler, there are a few more features the example code depends on.
 
 #### SRecord Tools
 
-The makefile assumes srecord tools, which you can install with:
+The build environment uses srecord tools, which you can install with:
 
 ```bash
 sudo apt install srecord
 ```
 
-#### CHERIoT RTOS SDK Installation
+#### CHERIoT LLVM
 
-You will need a copy of [CHERIoT RTOS](https://github.com/microsoft/cheriot-rtos/tree/main) for this section.
-
-On Windows you may need to set `git config --global core.symlinks true` *before* cloning the repository.
-
-Clone the repository somewhere, *not* into the root of the `sonata-system` directory, but at the same level as `sonata-system`:
-
-```sh
-cd ..
-git clone --recurse https://github.com/microsoft/cheriot-rtos.git
-```
-
-**IMPORTANT**: Set these two environmental variables. The first should point to the llvm build you did in the previous part,
-and the second should point to the `cheriot-rtos` repo you just checked out:
+**IMPORTANT**: Set this environmental variable to the llvm build you did in the previous part:
 
 ```sh
 export CHERIOT_LLVM_BIN=/path/to/cheriot-llvm/bin
-export CHERIOT_RTOS_SDK=/path/to/cheriot-rtos/sdk
 ```
 
 > WARNING: The path to `/path/to/cheriot-llvm/bin` should point to the *build* directory you created, not just the root checked out `cheriot-llvm` directory.
 > The path will look something like: `~/llvm-tools/cheriot-llvm/builds/cheriot-llvm/bin`
 
-The following assume you have run the `source .venv/bin/activate` command in the terminal you are using, and you are
-currently at the root directory of your local `sonata-system` git repository.
-
-### Building Baremetal Examples
+Please make sure you unset the `CHERIOT_RTOS_SDK` environment variable as `cmake` will automatically pull in [the correct version](https://github.com/lowRISC/cheriot-rtos/tree/sonata).
 
-> TODO: We should tell them where to get the SW. And especially point out it must match
-> the bitstream version again (all downloaded at one point).
+The following assumes you have run the `source .venv/bin/activate` command in the terminal you are using, and you are currently at the root directory of your local `sonata-system` git repository.
 
-> TODO: These environmental variables don't seem to be used by CMAKE but would need to be based.
-> So these instructions are broken but kept as a starting point.
+### Building Baremetal Examples
 
 To build, run the following from the root of the directory which will build the examples:
 
@@ -84,13 +66,12 @@ cmake -B sw/cheri/build -S sw/cheri
 cmake --build sw/cheri/build
 ```
 The build output is put in the `sw/cheri/build` directory.
-Two files of interest are created for each target: an ELF file which has no extension and a `*.vmem` file. The
-`*.vmem` file can be used to load directly into the FPGA bitstream, described in more detail on the [Programming the Sonata Software](../dev/sw-programming.md) page.
+Two files of interest are created for each target: an ELF file which has no extension and a `*.vmem` file.
+The `*.vmem` file can be used to load directly into the FPGA bitstream, described in more detail on the [Programming the Sonata Software](../dev/sw-programming.md) page.
 
-> If you get an error that `CMake will not be able to correctly generate this project.`, check
-> back in the list to see if you see an error within the output similar to 
-> `clang: error: unknown argument: '-mxcheri-rvc'`. If this happens it means the wrong (non-CHERIoT)
-> compiler was used. Check back to see what compiler is being used.
+> If you get an error that `CMake will not be able to correctly generate this project.`, check back in the list to see if you see an error within the output similar to `clang: error: unknown argument: '-mxcheri-rvc'`.
+> If this happens it means the wrong (non-CHERIoT) compiler was used.
+> Check back to see what compiler is being used.
 
 ### Loading software onto the FPGA
 
@@ -99,5 +80,4 @@ You can load software onto the FPGA over USB (JTAG) using:
 ```sh
 ./util/mem_helper.sh load_program -e sw/cheri/build/tests/spi_test
 ```
-There are actually four different ways of loading the program - we normally use JTAG for development, but you can also
-program it into the serial flash device on the board. See the page [Programming the Sonata Software](../dev/sw-programming.md).
+There are actually four different ways of loading the program - we normally use JTAG for development, but you can also program it into the serial flash device on the board. See the page [Programming the Sonata Software](../dev/sw-programming.md).