diff --git a/artiq/firmware/Cargo.lock b/artiq/firmware/Cargo.lock
index 863b990a0..044d1ff8f 100644
--- a/artiq/firmware/Cargo.lock
+++ b/artiq/firmware/Cargo.lock
@@ -30,7 +30,7 @@ dependencies = [
  "byteorder 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "cc 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "compiler_builtins 0.1.0 (git+https://github.com/m-labs/compiler-builtins?rev=1c765ad)",
- "smoltcp 0.4.0 (git+https://github.com/m-labs/smoltcp?rev=888b1d2)",
+ "smoltcp 0.4.0 (git+https://github.com/m-labs/smoltcp?rev=181083f)",
 ]
 
 [[package]]
@@ -52,7 +52,7 @@ dependencies = [
  "build_misoc 0.0.0",
  "byteorder 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "crc 1.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "smoltcp 0.4.0 (git+https://github.com/m-labs/smoltcp?rev=888b1d2)",
+ "smoltcp 0.4.0 (git+https://github.com/m-labs/smoltcp?rev=181083f)",
 ]
 
 [[package]]
@@ -218,7 +218,7 @@ dependencies = [
  "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "logger_artiq 0.0.0",
  "proto 0.0.0",
- "smoltcp 0.4.0 (git+https://github.com/m-labs/smoltcp?rev=888b1d2)",
+ "smoltcp 0.4.0 (git+https://github.com/m-labs/smoltcp?rev=181083f)",
  "std_artiq 0.0.0",
 ]
 
@@ -249,7 +249,7 @@ dependencies = [
 [[package]]
 name = "smoltcp"
 version = "0.4.0"
-source = "git+https://github.com/m-labs/smoltcp?rev=888b1d2#888b1d2403de79083ad9840ea8c6d93039555db3"
+source = "git+https://github.com/m-labs/smoltcp?rev=181083f#181083f18c977b8a0463a67e360e4db20594fa21"
 dependencies = [
  "byteorder 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -297,7 +297,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum log_buffer 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ec57723b84bbe7bdf76aa93169c9b59e67473317c6de3a83cb2a0f8ccb2aa493"
 "checksum managed 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "786bd3519bdfb0e1a57146a74b7584555dd6c4f1b6e1137c70e177d60dde8186"
 "checksum same-file 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "d931a44fdaa43b8637009e7632a02adc4f2b2e0733c08caa4cf00e8da4a117a7"
-"checksum smoltcp 0.4.0 (git+https://github.com/m-labs/smoltcp?rev=888b1d2)" = "<none>"
+"checksum smoltcp 0.4.0 (git+https://github.com/m-labs/smoltcp?rev=181083f)" = "<none>"
 "checksum walkdir 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)" = "bb08f9e670fab86099470b97cd2b252d6527f0b3cc1401acdb595ffc9dd288ff"
 "checksum winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "167dc9d6949a9b857f3451275e911c3f44255842c1f7a76f33c55103a909087a"
 "checksum winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2d315eee3b34aca4797b2da6b13ed88266e6d612562a0c46390af8299fc699bc"
diff --git a/artiq/firmware/bootloader/Cargo.toml b/artiq/firmware/bootloader/Cargo.toml
index 5d479ddd9..506a56a9b 100644
--- a/artiq/firmware/bootloader/Cargo.toml
+++ b/artiq/firmware/bootloader/Cargo.toml
@@ -19,6 +19,6 @@ board = { path = "../libboard", features = ["uart_console", "smoltcp"] }
 
 [dependencies.smoltcp]
 git = "https://github.com/m-labs/smoltcp"
-rev = "888b1d2"
+rev = "181083f"
 default-features = false
 features = ["proto-ipv4", "socket-tcp"]
diff --git a/artiq/firmware/libboard/Cargo.toml b/artiq/firmware/libboard/Cargo.toml
index 111d66738..f00a23abc 100644
--- a/artiq/firmware/libboard/Cargo.toml
+++ b/artiq/firmware/libboard/Cargo.toml
@@ -22,7 +22,7 @@ features = ["mem"]
 
 [dependencies.smoltcp]
 git = "https://github.com/m-labs/smoltcp"
-rev = "888b1d2"
+rev = "181083f"
 default-features = false
 optional = true
 
diff --git a/artiq/firmware/runtime/Cargo.toml b/artiq/firmware/runtime/Cargo.toml
index 0d3514c12..e76add67b 100644
--- a/artiq/firmware/runtime/Cargo.toml
+++ b/artiq/firmware/runtime/Cargo.toml
@@ -35,6 +35,6 @@ features = ["alloc"]
 
 [dependencies.smoltcp]
 git = "https://github.com/m-labs/smoltcp"
-rev = "888b1d2"
+rev = "181083f"
 default-features = false
 features = ["alloc", "log", "proto-ipv4", "socket-tcp"]