diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
index 968e1f2..d25b2e6 100644
--- a/.github/workflows/rust.yml
+++ b/.github/workflows/rust.yml
@@ -59,6 +59,7 @@ jobs:
     - name: build and fmt beginner/apps
       working-directory: ./beginner/apps
       run: |
+        cargo install flip-link
         cargo build --verbose
         cargo fmt --all -- --check
 
diff --git a/advanced/firmware/Cargo.toml b/advanced/firmware/Cargo.toml
index f7df825..dca67df 100644
--- a/advanced/firmware/Cargo.toml
+++ b/advanced/firmware/Cargo.toml
@@ -25,11 +25,11 @@ usb2 = { git = "https://github.com/japaric/usb2" }
 # optimize code in both profiles
 [profile.dev]
 codegen-units = 1
-debug = 2
+debug = 1
 debug-assertions = true # !
 incremental = false
 lto = "fat"
-opt-level = 1 # !
+opt-level = 'z' # !
 overflow-checks = false
 
 [profile.release]
diff --git a/advanced/firmware/src/bin/stack_overflow.rs b/advanced/firmware/src/bin/stack_overflow.rs
index befc47b..e24c08f 100644
--- a/advanced/firmware/src/bin/stack_overflow.rs
+++ b/advanced/firmware/src/bin/stack_overflow.rs
@@ -25,6 +25,5 @@ fn spam() {
 
     log::info!("address of current `use_stack`: {:?}", &use_stack as *const u32);
 
-    log::info!("entering next recursive step");
     spam(); // infinite recursion
 }
diff --git a/beginner/apps/.cargo/config.toml b/beginner/apps/.cargo/config.toml
index 1f11e40..be9aeec 100644
--- a/beginner/apps/.cargo/config.toml
+++ b/beginner/apps/.cargo/config.toml
@@ -1,3 +1,10 @@
+[target.'cfg(all(target_arch = "arm", target_os = "none"))']
+# (..)
+rustflags = [
+  "-C", "linker=flip-link", # adds stack overflow protection
+  # (..)
+]
+
 [target.thumbv7em-none-eabihf]
 runner = "probe-run --chip nRF52840_xxAA"
 rustflags = [
diff --git a/embedded-workshop-book/src/installation.md b/embedded-workshop-book/src/installation.md
index d042a4f..f12dec0 100644
--- a/embedded-workshop-book/src/installation.md
+++ b/embedded-workshop-book/src/installation.md
@@ -143,6 +143,10 @@ Installed package `cargo-binutils v0.3.3` (..)
 $ cargo install probe-run
 (..)
 Installed package `probe-run v0.1.8` (..)
+
+$ cargo install flip-link
+(..)
+Installed package `flip-link v0.1.2` (..)
 ```
 
 ### Workshop specific tools
@@ -176,12 +180,6 @@ Leave the processes running in the background.
 
 #### Advanced workshop
 
-```console
-$ cargo install flip-link
-(..)
-Installed package `flip-link v0.1.2` (..)
-```
-
 Change to the `tools` folder and run these commands:
 
 ```console