diff --git a/firmware/build.sh b/firmware/build.sh
index f5e3670..bf4acd4 100755
--- a/firmware/build.sh
+++ b/firmware/build.sh
@@ -23,7 +23,7 @@ svd2rust -i $BUILD_DIR/csr.svd --target riscv
 
 # Build the firmware .elf file
 cd $FW_ROOT/litex-fw
-cargo build --target=riscv32imac-unknown-none-elf
+cargo build --target=riscv32imac-unknown-none-elf --release
 
 # Copy it into a binary that litex_term can upload.
-${OBJCOPY} target/riscv32imac-unknown-none-elf/debug/litex-fw -O binary $BUILD_DIR/rust-fw.bin
+${OBJCOPY} target/riscv32imac-unknown-none-elf/release/litex-fw -O binary $BUILD_DIR/rust-fw.bin
diff --git a/firmware/litex-fw/.cargo/config b/firmware/litex-fw/.cargo/config
index c356dba..9b25266 100644
--- a/firmware/litex-fw/.cargo/config
+++ b/firmware/litex-fw/.cargo/config
@@ -8,3 +8,6 @@ rustflags = [
 
 [build]
 target = "riscv32imac-unknown-none-elf"
+
+[profile.release]
+opt-level = 1