diff --git a/firmware/.cargo/config.toml b/firmware/.cargo/config.toml
index 67b24524..b18ce923 100644
--- a/firmware/.cargo/config.toml
+++ b/firmware/.cargo/config.toml
@@ -9,4 +9,5 @@ rustflags = [
 rustflags = [
     "-C", "link-arg=-Tlink.x",
     "-C", "link-arg=-Tdefmt.x",
+    "-C", "opt-level=z",
 ]
diff --git a/firmware/Cargo.toml b/firmware/Cargo.toml
index 557ecfe3..f5b0c6e7 100644
--- a/firmware/Cargo.toml
+++ b/firmware/Cargo.toml
@@ -116,3 +116,5 @@ undocumented_unsafe_blocks = "deny"
 codegen-units = 1
 lto = "fat"
 opt-level = 3  # "s"/"z" break Xtensa (l32r literal range exceeded)
+panic = "abort"
+strip = true
diff --git a/firmware/src/display/mod.rs b/firmware/src/display/mod.rs
index bb78536d..c92bc917 100644
--- a/firmware/src/display/mod.rs
+++ b/firmware/src/display/mod.rs
@@ -1,6 +1,7 @@
 //! OLED display driver with radio status dashboard.
 
 mod render;
+#[cfg(feature = "wio_tracker_l1")]
 pub mod sh1106;
 mod task;
 pub use task::display_task;
diff --git a/firmware/src/display/render.rs b/firmware/src/display/render.rs
index 2c3145d2..8914acfd 100644
--- a/firmware/src/display/render.rs
+++ b/firmware/src/display/render.rs
@@ -34,6 +34,7 @@ pub struct BoardInfo<'a> {
 }
 
 /// Render the active dashboard (shown when radio is in RX or TX mode).
+#[allow(clippy::too_many_arguments)]
 pub fn dashboard(
     target: &mut impl DrawTarget<Color = BinaryColor>,
     status: &RadioStatus,
@@ -289,6 +290,7 @@ fn compact_count(n: u32) -> String<10> {
 ///
 /// The current (uncommitted) slot is rendered at the rightmost position
 /// so that incoming packets appear on the graph immediately.
+#[allow(clippy::too_many_arguments)]
 fn rssi_sparkline(
     target: &mut impl DrawTarget<Color = BinaryColor>,
     history: &[i16; RSSI_HISTORY_LEN],
diff --git a/firmware/src/display/sh1106.rs b/firmware/src/display/sh1106.rs
index 7216e8d8..c5cc2a15 100644
--- a/firmware/src/display/sh1106.rs
+++ b/firmware/src/display/sh1106.rs
@@ -74,7 +74,7 @@ impl<I: I2c> Sh1106<I> {
             // Set page address and column start (with SH1106 2-column offset).
             self.cmd(&[
                 0xB0 | page as u8,          // page address
-                0x00 | (COL_OFFSET & 0x0F), // column low nibble
+                COL_OFFSET & 0x0F, // column low nibble
                 0x10 | (COL_OFFSET >> 4),   // column high nibble
             ])
             .await?;
@@ -91,10 +91,6 @@ impl<I: I2c> Sh1106<I> {
         self.cmd(&[0x81, value]).await
     }
 
-    /// Clear the framebuffer (call flush() to update the display).
-    pub fn clear_buffer(&mut self) {
-        self.buffer.fill(0);
-    }
 }
 
 impl<I: I2c> DrawTarget for Sh1106<I> {
diff --git a/firmware/src/protocol.rs b/firmware/src/protocol.rs
index 6f05bef4..3cf01d52 100644
--- a/firmware/src/protocol.rs
+++ b/firmware/src/protocol.rs
@@ -328,6 +328,8 @@ mod tests {
                 cr: 8,
                 sync_word: 0x1234,
                 tx_power_dbm: -9,
+                preamble_len: 16,
+                cad: 1,
             };
             let mut buf = [0u8; RADIO_CONFIG_SIZE];
             cfg.write_to(&mut buf);