Update IMU readme

Signed-off-by: Sindy Tan <sindytn@gmail.com>
Change-Id: Ie9b2e53296b01ebff41faa04aedc43b9616bd38c
diff --git a/frc971/imu_fdcan/README.md b/frc971/imu_fdcan/README.md
index 8e82f73..7bf7328 100644
--- a/frc971/imu_fdcan/README.md
+++ b/frc971/imu_fdcan/README.md
@@ -23,7 +23,8 @@
     * The main code lives in [`Dual_IMU/Core/Src`](/Dual_IMU/Core/Src/). Make sure your changes happen inside sections marked `/* USER CODE BEGIN ... */` `/* USER CODE END ... */`. Code outside these markers will be overwritten by CubeIDE when generating code after changes to the `.ioc` file.
 3) Build + Run:
     * Option 1: Open CubeIDE GUI to build, debug, or run.
-    * Option 2: 
+    <!-- TODO(sindy): fix this build script -->
+    * Option 2 (DO NOT USE. NOT SAFE) 
         1) SSH onto the build server. 
         2) Run `bazel build -c opt --config=cortex-m4f-imu //frc971/imu_fdcan/Dual_IMU/Core:main.elf`. The output .elf file should be in bazel-bin/frc971/imu_fdcan/Dual_IMU/Core.
         3) (If deploying code locally) Move file to local directory. For example: `scp <username>@build.frc971.org:<path/to/main.elf> <local/path/to/save/file/`. A good spot to put this locally is ./Dual_IMU/Debug/.