diff --git a/Cargo.toml b/Cargo.toml
index dcef60b5..667afa8f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -48,7 +48,7 @@ fdcan = { version = "0.2", optional = true }
 embedded-storage = "0.3"
 
 [dependencies.smoltcp]
-version = "0.11.0"
+version = "0.12.0"
 default-features = false
 features = ["medium-ethernet", "proto-ipv4", "socket-raw"]
 optional = true
diff --git a/src/ethernet/eth.rs b/src/ethernet/eth.rs
index b825595b..5177a3fd 100644
--- a/src/ethernet/eth.rs
+++ b/src/ethernet/eth.rs
@@ -816,7 +816,7 @@ pub struct RxToken<'a, const RD: usize>(&'a mut RDesRing<RD>);
 impl<'a, const RD: usize> phy::RxToken for RxToken<'a, RD> {
     fn consume<R, F>(self, f: F) -> R
     where
-        F: FnOnce(&mut [u8]) -> R,
+        F: FnOnce(&[u8]) -> R,
     {
         let result = f(unsafe { self.0.buf_as_slice_mut() });
         self.0.release();