diff --git a/Cargo.lock b/Cargo.lock
index bab6921a..e5609d48 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -5,16 +5,41 @@ name = "bit_field"
 version = "0.10.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "bitflags"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "byteorder"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "compiler_builtins"
-version = "0.1.16"
-source = "git+https://github.com/rust-lang-nursery/compiler-builtins#5e06435c291211a6443d3b29b948faa3ccaaa180"
+version = "0.1.19"
+source = "git+https://github.com/rust-lang-nursery/compiler-builtins#36da64f20e96206ac279f700586817c8abe3bdf8"
+
+[[package]]
+name = "managed"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "r0"
 version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "smoltcp"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "bitflags 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "managed 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "vcell"
 version = "0.1.0"
@@ -33,14 +58,19 @@ name = "zc706"
 version = "0.0.0"
 dependencies = [
  "bit_field 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.16 (git+https://github.com/rust-lang-nursery/compiler-builtins)",
+ "compiler_builtins 0.1.19 (git+https://github.com/rust-lang-nursery/compiler-builtins)",
  "r0 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "smoltcp 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "volatile-register 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [metadata]
 "checksum bit_field 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)" = "a165d606cf084741d4ac3a28fb6e9b1eb0bd31f6cd999098cfddb0b2ab381dc0"
-"checksum compiler_builtins 0.1.16 (git+https://github.com/rust-lang-nursery/compiler-builtins)" = "<none>"
+"checksum bitflags 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3d155346769a6855b86399e9bc3814ab343cd3d62c7e985113d46a0ec3c281fd"
+"checksum byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)" = "a7c3dd8985a7111efc5c80b44e23ecdd8c007de8ade3b96595387e812b957cf5"
+"checksum compiler_builtins 0.1.19 (git+https://github.com/rust-lang-nursery/compiler-builtins)" = "<none>"
+"checksum managed 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)" = "fdcec5e97041c7f0f1c5b7d93f12e57293c831c646f4cc7a5db59460c7ea8de6"
 "checksum r0 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "e2a38df5b15c8d5c7e8654189744d8e396bddc18ad48041a500ce52d6948941f"
+"checksum smoltcp 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fef582369edb298c6c41319a544ca9c4e83622f226055ccfcb35974fbb55ed34"
 "checksum vcell 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "45c297f0afb6928cd08ab1ff9d95e99392595ea25ae1b5ecf822ff8764e57a0d"
 "checksum volatile-register 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0d67cb4616d99b940db1d6bd28844ff97108b498a6ca850e5b6191a532063286"