diff --git a/artiq/firmware/Cargo.lock b/artiq/firmware/Cargo.lock
index caf0d005f..2874347c8 100644
--- a/artiq/firmware/Cargo.lock
+++ b/artiq/firmware/Cargo.lock
@@ -33,7 +33,7 @@ dependencies = [
  "byteorder 1.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "cc 1.0.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "smoltcp 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "smoltcp 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -44,7 +44,7 @@ dependencies = [
  "build_misoc 0.0.0",
  "byteorder 1.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "crc 1.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "smoltcp 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "smoltcp 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -146,14 +146,6 @@ name = "libc"
 version = "0.2.40"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
-[[package]]
-name = "log"
-version = "0.3.9"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "log"
 version = "0.4.1"
@@ -218,7 +210,7 @@ dependencies = [
  "logger_artiq 0.0.0",
  "managed 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "proto_artiq 0.0.0",
- "smoltcp 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "smoltcp 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "unwind_backtrace 0.0.0",
 ]
 
@@ -234,12 +226,11 @@ dependencies = [
 
 [[package]]
 name = "smoltcp"
-version = "0.5.0"
+version = "0.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bitflags 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "managed 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -291,12 +282,11 @@ version = "0.0.0"
 "checksum failure_derive 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "c7cdda555bb90c9bb67a3b670a0f42de8e73f5981524123ad8578aafec8ddb8b"
 "checksum fringe 1.1.0 (git+https://github.com/m-labs/libfringe?rev=b8a6d8f)" = "<none>"
 "checksum libc 0.2.40 (registry+https://github.com/rust-lang/crates.io-index)" = "6fd41f331ac7c5b8ac259b8bf82c75c0fb2e469bbf37d2becbba9a6a2221965b"
-"checksum log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)" = "e19e8d5c34a3e0e2223db8e060f9e8264aeeb5c5fc64a4ee9965c062211c024b"
 "checksum log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)" = "89f010e843f2b1a31dbd316b3b8d443758bc634bed37aabade59c686d644e0a2"
 "checksum log_buffer 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "f033173c9486b7fe97a79c895c0a3483ae395ab6744c985d10078950e2492419"
 "checksum managed 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ba6713e624266d7600e9feae51b1926c6a6a6bebb18ec5a8e11a5f1d5661baba"
 "checksum quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6e920b65c65f10b2ae65c831a81a073a89edd28c7cce89475bff467ab4167a"
-"checksum smoltcp 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fef582369edb298c6c41319a544ca9c4e83622f226055ccfcb35974fbb55ed34"
+"checksum smoltcp 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0fe46639fd2ec79eadf8fe719f237a7a0bd4dac5d957f1ca5bbdbc1c3c39e53a"
 "checksum syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)" = "d3b891b9015c88c576343b9b3e41c2c11a51c219ef067b264bd9c8aa9b441dad"
 "checksum synom 0.11.3 (registry+https://github.com/rust-lang/crates.io-index)" = "a393066ed9010ebaed60b9eafa373d4b1baac186dd7e008555b0f702b51945b6"
 "checksum synstructure 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)" = "3a761d12e6d8dcb4dcf952a7a89b475e3a9d69e4a69307e01a470977642914bd"
diff --git a/artiq/firmware/bootloader/Cargo.toml b/artiq/firmware/bootloader/Cargo.toml
index aed6df31b..e89902308 100644
--- a/artiq/firmware/bootloader/Cargo.toml
+++ b/artiq/firmware/bootloader/Cargo.toml
@@ -16,4 +16,4 @@ build_misoc = { path = "../libbuild_misoc" }
 byteorder = { version = "1.0", default-features = false }
 crc = { version = "1.7", default-features = false }
 board_misoc = { path = "../libboard_misoc", features = ["uart_console", "smoltcp"] }
-smoltcp = { version = "0.5.0", default-features = false, features = ["proto-ipv4", "proto-ipv6", "socket-tcp"] }
+smoltcp = { version = "0.6.0", default-features = false, features = ["ethernet", "proto-ipv4", "proto-ipv6", "socket-tcp"] }
diff --git a/artiq/firmware/cargosha256.nix b/artiq/firmware/cargosha256.nix
index c356e4291..2bf5725cf 100644
--- a/artiq/firmware/cargosha256.nix
+++ b/artiq/firmware/cargosha256.nix
@@ -1 +1 @@
-"1xzjn9i4rkd9124v2gbdplsgsvp1hlx7czdgc58n316vsnrkbr86"
+"0ml6j4sxqrayqk25xkrikwg713mahfqa60nrx1jhrj8c2h3p07yk"
diff --git a/artiq/firmware/libboard_misoc/Cargo.toml b/artiq/firmware/libboard_misoc/Cargo.toml
index 8847d0a0d..81ebf979f 100644
--- a/artiq/firmware/libboard_misoc/Cargo.toml
+++ b/artiq/firmware/libboard_misoc/Cargo.toml
@@ -15,7 +15,7 @@ build_misoc = { path = "../libbuild_misoc" }
 [dependencies]
 byteorder = { version = "1.0", default-features = false }
 log = { version = "0.4", default-features = false, optional = true }
-smoltcp = { version = "0.5.0", default-features = false, optional = true }
+smoltcp = { version = "0.6.0", default-features = false, optional = true }
 
 [features]
 uart_console = []
diff --git a/artiq/firmware/libboard_misoc/ethmac.rs b/artiq/firmware/libboard_misoc/ethmac.rs
index 263f8122d..ff585a010 100644
--- a/artiq/firmware/libboard_misoc/ethmac.rs
+++ b/artiq/firmware/libboard_misoc/ethmac.rs
@@ -30,7 +30,7 @@ fn next_tx_slot() -> Option<usize> {
     }
 }
 
-fn rx_buffer(slot: usize) -> *const u8 {
+fn rx_buffer(slot: usize) -> *mut u8 {
     debug_assert!(slot < RX_SLOTS);
     (ETHMAC_BASE + SLOT_SIZE * slot) as _
 }
@@ -97,11 +97,11 @@ pub struct EthernetRxSlot(usize);
 
 impl phy::RxToken for EthernetRxSlot {
     fn consume<R, F>(self, _timestamp: Instant, f: F) -> Result<R>
-        where F: FnOnce(&[u8]) -> Result<R>
+        where F: FnOnce(&mut [u8]) -> Result<R>
     {
         unsafe {
             let length = csr::ethmac::sram_writer_length_read() as usize;
-            let result = f(slice::from_raw_parts(rx_buffer(self.0), length));
+            let result = f(slice::from_raw_parts_mut(rx_buffer(self.0), length));
             csr::ethmac::sram_writer_ev_pending_write(1);
             result
         }
diff --git a/artiq/firmware/runtime/Cargo.toml b/artiq/firmware/runtime/Cargo.toml
index c2404fc4c..bbb9877bb 100644
--- a/artiq/firmware/runtime/Cargo.toml
+++ b/artiq/firmware/runtime/Cargo.toml
@@ -27,7 +27,7 @@ board_misoc = { path = "../libboard_misoc", features = ["uart_console", "smoltcp
 logger_artiq = { path = "../liblogger_artiq" }
 board_artiq = { path = "../libboard_artiq" }
 proto_artiq = { path = "../libproto_artiq", features = ["log", "alloc"] }
-smoltcp = { version = "0.5.0", default-features = false, features = ["rust-1_28", "alloc", "log", "proto-ipv4", "proto-ipv6", "socket-tcp"] }
+smoltcp = { version = "0.6.0", default-features = false, features = ["rust-1_28", "alloc", "ethernet", "proto-ipv4", "proto-ipv6", "socket-tcp"] }
 
 [dependencies.fringe]
 git = "https://github.com/m-labs/libfringe"