diff --git a/src/Cargo.lock b/src/Cargo.lock
index 4e3a97e8..e0770544 100644
--- a/src/Cargo.lock
+++ b/src/Cargo.lock
@@ -203,7 +203,7 @@ dependencies = [
 [[package]]
 name = "libasync"
 version = "0.0.0"
-source = "git+https://git.m-labs.hk/M-Labs/zynq-rs.git#273f9ea72b738c1c85fdc398c3486c2f0564881e"
+source = "git+https://git.m-labs.hk/M-Labs/zynq-rs.git#a73df780d0d0e757738f27feac162904f5bf93f9"
 dependencies = [
  "embedded-hal",
  "libcortex_a9",
@@ -215,7 +215,7 @@ dependencies = [
 [[package]]
 name = "libboard_zynq"
 version = "0.0.0"
-source = "git+https://git.m-labs.hk/M-Labs/zynq-rs.git#273f9ea72b738c1c85fdc398c3486c2f0564881e"
+source = "git+https://git.m-labs.hk/M-Labs/zynq-rs.git#a73df780d0d0e757738f27feac162904f5bf93f9"
 dependencies = [
  "bit_field",
  "embedded-hal",
@@ -249,7 +249,7 @@ dependencies = [
 [[package]]
 name = "libcortex_a9"
 version = "0.0.0"
-source = "git+https://git.m-labs.hk/M-Labs/zynq-rs.git#273f9ea72b738c1c85fdc398c3486c2f0564881e"
+source = "git+https://git.m-labs.hk/M-Labs/zynq-rs.git#a73df780d0d0e757738f27feac162904f5bf93f9"
 dependencies = [
  "bit_field",
  "libregister",
@@ -265,7 +265,7 @@ checksum = "c7d73b3f436185384286bd8098d17ec07c9a7d2388a6599f824d8502b529702a"
 [[package]]
 name = "libregister"
 version = "0.0.0"
-source = "git+https://git.m-labs.hk/M-Labs/zynq-rs.git#273f9ea72b738c1c85fdc398c3486c2f0564881e"
+source = "git+https://git.m-labs.hk/M-Labs/zynq-rs.git#a73df780d0d0e757738f27feac162904f5bf93f9"
 dependencies = [
  "bit_field",
  "vcell",
@@ -275,7 +275,7 @@ dependencies = [
 [[package]]
 name = "libsupport_zynq"
 version = "0.0.0"
-source = "git+https://git.m-labs.hk/M-Labs/zynq-rs.git#273f9ea72b738c1c85fdc398c3486c2f0564881e"
+source = "git+https://git.m-labs.hk/M-Labs/zynq-rs.git#a73df780d0d0e757738f27feac162904f5bf93f9"
 dependencies = [
  "compiler_builtins",
  "libboard_zynq",
diff --git a/src/libconfig/src/net_settings.rs b/src/libconfig/src/net_settings.rs
index 8c2a24ef..76ddbb26 100644
--- a/src/libconfig/src/net_settings.rs
+++ b/src/libconfig/src/net_settings.rs
@@ -1,22 +1,30 @@
 use core::fmt;
 
 use libboard_zynq::smoltcp::wire::{EthernetAddress, IpAddress};
+
 use super::Config;
 
 pub struct NetAddresses {
     pub hardware_addr: EthernetAddress,
     pub ipv4_addr: IpAddress,
+    #[cfg(feature = "ipv6")]
     pub ipv6_ll_addr: IpAddress,
+    #[cfg(feature = "ipv6")]
     pub ipv6_addr: Option<IpAddress>
 }
 
 impl fmt::Display for NetAddresses {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "MAC={} IPv4={} IPv6-LL={} IPv6=",
-            self.hardware_addr, self.ipv4_addr, self.ipv6_ll_addr)?;
-        match self.ipv6_addr {
-            Some(addr) => write!(f, "{}", addr)?,
-            None => write!(f, "no configured address")?
+        write!(f, "MAC={} IPv4={} ",
+            self.hardware_addr, self.ipv4_addr)?;
+
+        #[cfg(feature = "ipv6")]
+        {
+            write!(f, "IPv6-LL={}", self.ipv6_ll_addr)?;
+            match self.ipv6_addr {
+                Some(addr) => write!(f, " {}", addr)?,
+                None => write!(f, " IPv6: no configured address")?
+            }
         }
         Ok(())
     }
@@ -25,7 +33,6 @@ impl fmt::Display for NetAddresses {
 pub fn get_adresses(cfg: &Config) -> NetAddresses {
     let mut hardware_addr = EthernetAddress([0x02, 0x00, 0x00, 0x00, 0x00, 0x52]);
     let mut ipv4_addr = IpAddress::v4(192, 168, 1, 52);
-    let mut ipv6_addr = None;
 
     if let Ok(Ok(addr)) = cfg.read_str("mac").map(|s| s.parse()) {
         hardware_addr = addr;
@@ -33,10 +40,10 @@ pub fn get_adresses(cfg: &Config) -> NetAddresses {
     if let Ok(Ok(addr)) = cfg.read_str("ip").map(|s| s.parse()) {
         ipv4_addr = addr;
     }
-    if let Ok(Ok(addr)) = cfg.read_str("ip6").map(|s| s.parse()) {
-        ipv6_addr = Some(addr);
-    }
+    #[cfg(feature = "ipv6")]
+    let ipv6_addr = cfg.read_str("ipv6").ok().and_then(|s| s.parse().ok());
 
+    #[cfg(feature = "ipv6")]
     let ipv6_ll_addr = IpAddress::v6(
         0xfe80, 0x0000, 0x0000, 0x0000,
         (((hardware_addr.0[0] ^ 0x02) as u16) << 8) | (hardware_addr.0[1] as u16),
@@ -45,9 +52,11 @@ pub fn get_adresses(cfg: &Config) -> NetAddresses {
         ((hardware_addr.0[4] as u16) << 8) | (hardware_addr.0[5] as u16));
 
     NetAddresses {
-        hardware_addr: hardware_addr,
-        ipv4_addr: ipv4_addr,
-        ipv6_ll_addr: ipv6_ll_addr,
-        ipv6_addr: ipv6_addr
+        hardware_addr,
+        ipv4_addr,
+        #[cfg(feature = "ipv6")]
+        ipv6_ll_addr,
+        #[cfg(feature = "ipv6")]
+        ipv6_addr
     }
 }
diff --git a/src/runtime/Cargo.toml b/src/runtime/Cargo.toml
index 6385fe0c..88e42502 100644
--- a/src/runtime/Cargo.toml
+++ b/src/runtime/Cargo.toml
@@ -25,7 +25,7 @@ log_buffer = { version = "1.2" }
 libm = { version = "0.2", features = ["unstable"] }
 vcell = "0.1"
 
-libboard_zynq = { git = "https://git.m-labs.hk/M-Labs/zynq-rs.git" }
+libboard_zynq = { git = "https://git.m-labs.hk/M-Labs/zynq-rs.git", features = ["ipv6"]}
 libsupport_zynq = { default-features = false, features = ["alloc_core"], git = "https://git.m-labs.hk/M-Labs/zynq-rs.git" }
 libcortex_a9 = { git = "https://git.m-labs.hk/M-Labs/zynq-rs.git" }
 libasync = { git = "https://git.m-labs.hk/M-Labs/zynq-rs.git" }
@@ -35,4 +35,4 @@ dyld = { path = "../libdyld" }
 dwarf = { path = "../libdwarf" }
 unwind = { path = "../libunwind" }
 libc = { path = "../libc" }
-libconfig = { path = "../libconfig" }
+libconfig = { path = "../libconfig", features = ["ipv6"]}