diff --git a/artiq/firmware/bootloader/Cargo.toml b/artiq/firmware/bootloader/Cargo.toml
index 2a43b72f5..aed6df31b 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", "socket-tcp"] }
+smoltcp = { version = "0.5.0", default-features = false, features = ["proto-ipv4", "proto-ipv6", "socket-tcp"] }
diff --git a/artiq/firmware/bootloader/main.rs b/artiq/firmware/bootloader/main.rs
index fc084d5e4..545e3a73c 100644
--- a/artiq/firmware/bootloader/main.rs
+++ b/artiq/firmware/bootloader/main.rs
@@ -12,7 +12,7 @@ use crc::crc32;
 use byteorder::{ByteOrder, BigEndian};
 use board_misoc::{ident, cache, sdram, boot, mem as board_mem};
 #[cfg(has_ethmac)]
-use board_misoc::{clock, config, ethmac};
+use board_misoc::{clock, config, ethmac, net_settings};
 use board_misoc::uart_console::Console;
 
 fn check_integrity() -> bool {
@@ -155,18 +155,6 @@ fn network_boot() {
 
     println!("Initializing network...");
 
-    let eth_addr = match config::read_str("mac", |r| r.map(|s| s.parse())) {
-        Ok(Ok(addr)) => addr,
-        _ => EthernetAddress([0x02, 0x00, 0x00, 0x00, 0x00, 0x01])
-    };
-
-    let ip_addr = match config::read_str("ip", |r| r.map(|s| s.parse())) {
-        Ok(Ok(addr)) => addr,
-        _ => IpAddress::v4(192, 168, 1, 50)
-    };
-
-    println!("Using MAC address {} and IP address {}", eth_addr, ip_addr);
-
     let mut net_device = unsafe { ethmac::EthernetDevice::new() };
     net_device.reset_phy_if_any();
 
@@ -174,12 +162,33 @@ fn network_boot() {
     let neighbor_cache =
         smoltcp::iface::NeighborCache::new(&mut neighbor_map[..]);
     let mut ip_addrs = [IpCidr::new(ip_addr, 0)];
-    let mut interface  =
-        smoltcp::iface::EthernetInterfaceBuilder::new(net_device)
+    let net_addresses = net_settings::get_adresses();
+    println!("network addresses: {}", net_addresses);
+    let mut interface = match net_addresses.ipv6_addr {
+        Some(addr) => {
+            let ip_addrs = [
+                IpCidr::new(net_addresses.ipv4_addr, 0),
+                IpCidr::new(net_addresses.ipv6_ll_addr, 0),
+                IpCidr::new(addr, 0)
+            ];
+            smoltcp::iface::EthernetInterfaceBuilder::new(net_device)
+                       .ethernet_addr(net_addresses.hardware_addr)
+                       .ip_addrs(ip_addrs)
                        .neighbor_cache(neighbor_cache)
-                       .ethernet_addr(eth_addr)
-                       .ip_addrs(&mut ip_addrs[..])
-                       .finalize();
+                       .finalize()
+        }
+        None => {
+            let ip_addrs = [
+                IpCidr::new(net_addresses.ipv4_addr, 0),
+                IpCidr::new(net_addresses.ipv6_ll_addr, 0)
+            ];
+            smoltcp::iface::EthernetInterfaceBuilder::new(net_device)
+                       .ethernet_addr(net_addresses.hardware_addr)
+                       .ip_addrs(ip_addrs)
+                       .neighbor_cache(neighbor_cache)
+                       .finalize()
+        }
+    };
 
     let mut socket_set_storage = [];
     let mut sockets =
diff --git a/artiq/firmware/libboard_artiq/lib.rs b/artiq/firmware/libboard_artiq/lib.rs
index ce0757427..9a4e727b2 100644
--- a/artiq/firmware/libboard_artiq/lib.rs
+++ b/artiq/firmware/libboard_artiq/lib.rs
@@ -17,7 +17,6 @@ extern crate proto_artiq;
 
 pub mod pcr;
 
-pub mod i2c;
 pub mod spi;
 
 #[cfg(has_kernel_cpu)]
@@ -25,12 +24,8 @@ pub mod mailbox;
 #[cfg(has_kernel_cpu)]
 pub mod rpc_queue;
 
-#[cfg(any(soc_platform = "kasli", has_si5324))]
-mod pca9548;
 #[cfg(has_si5324)]
 pub mod si5324;
-#[cfg(soc_platform = "kasli")]
-pub mod i2c_eeprom;
 
 #[cfg(has_slave_fpga_cfg)]
 pub mod slave_fpga;
diff --git a/artiq/firmware/libboard_artiq/pca9548.rs b/artiq/firmware/libboard_artiq/pca9548.rs
deleted file mode 100644
index a69d72ed7..000000000
--- a/artiq/firmware/libboard_artiq/pca9548.rs
+++ /dev/null
@@ -1,13 +0,0 @@
-use i2c;
-
-pub fn select(busno: u8, address: u8, channels: u8) -> Result<(), &'static str> {
-    i2c::start(busno).unwrap();
-    if !i2c::write(busno, address << 1)? {
-        return Err("PCA9548 failed to ack write address")
-    }
-    if !i2c::write(busno, channels)? {
-        return Err("PCA9548 failed to ack control word")
-    }
-    i2c::stop(busno).unwrap();
-    Ok(())
-}
diff --git a/artiq/firmware/libboard_artiq/si5324.rs b/artiq/firmware/libboard_artiq/si5324.rs
index d02bec693..68005131f 100644
--- a/artiq/firmware/libboard_artiq/si5324.rs
+++ b/artiq/firmware/libboard_artiq/si5324.rs
@@ -1,9 +1,7 @@
 use core::result;
-use board_misoc::clock;
+use board_misoc::{clock, i2c};
 #[cfg(not(si5324_soft_reset))]
 use board_misoc::csr;
-use i2c;
-use pca9548;
 
 type Result<T> = result::Result<T, &'static str>;
 
@@ -181,15 +179,15 @@ fn init() -> Result<()> {
 
     #[cfg(soc_platform = "kasli")]
     {
-        pca9548::select(BUSNO, 0x70, 0)?;
-        pca9548::select(BUSNO, 0x71, 1 << 3)?;
+        i2c::pca9548_select(BUSNO, 0x70, 0)?;
+        i2c::pca9548_select(BUSNO, 0x71, 1 << 3)?;
     }
     #[cfg(soc_platform = "sayma_amc")]
-    pca9548::select(BUSNO, 0x70, 1 << 4)?;
+    i2c::pca9548_select(BUSNO, 0x70, 1 << 4)?;
     #[cfg(soc_platform = "sayma_rtm")]
-    pca9548::select(BUSNO, 0x77, 1 << 5)?;
+    i2c::pca9548_select(BUSNO, 0x77, 1 << 5)?;
     #[cfg(soc_platform = "kc705")]
-    pca9548::select(BUSNO, 0x74, 1 << 7)?;
+    i2c::pca9548_select(BUSNO, 0x74, 1 << 7)?;
 
     if ident()? != 0x0182 {
         return Err("Si5324 does not have expected product number");
diff --git a/artiq/firmware/libboard_artiq/i2c.rs b/artiq/firmware/libboard_misoc/i2c.rs
similarity index 89%
rename from artiq/firmware/libboard_artiq/i2c.rs
rename to artiq/firmware/libboard_misoc/i2c.rs
index d13dc32ce..b816c4921 100644
--- a/artiq/firmware/libboard_artiq/i2c.rs
+++ b/artiq/firmware/libboard_misoc/i2c.rs
@@ -1,6 +1,6 @@
 #[cfg(has_i2c)]
 mod imp {
-    use board_misoc::{csr, clock};
+    use super::super::{csr, clock};
 
     const INVALID_BUS: &'static str = "Invalid I2C bus";
 
@@ -46,7 +46,7 @@ mod imp {
         }
     }
 
-    pub fn init() {
+    pub fn init() -> Result<(), &'static str> {
         for busno in 0..csr::CONFIG_I2C_BUS_COUNT {
             let busno = busno as u8;
             // Set SCL as output, and high level
@@ -61,8 +61,6 @@ mod imp {
             half_period();
             half_period();
             if !sda_i(busno) {
-                warn!("SDA is stuck low on bus #{}, trying to unstuck", busno);
-
                 // Try toggling SCL a few times
                 for _bit in 0..8 {
                     scl_o(busno, false);
@@ -73,9 +71,10 @@ mod imp {
             }
 
             if !sda_i(busno) {
-                error!("SDA is stuck low on bus #{} and doesn't get unstuck", busno);
+                return Err("SDA is stuck low and doesn't get unstuck");
             }
         }
+        Ok(())
     }
 
     pub fn start(busno: u8) -> Result<(), &'static str> {
@@ -178,17 +177,30 @@ mod imp {
 
         Ok(data)
     }
+
+    pub fn pca9548_select(busno: u8, address: u8, channels: u8) -> Result<(), &'static str> {
+        start(busno)?;
+        if !write(busno, address << 1)? {
+            return Err("PCA9548 failed to ack write address")
+        }
+        if !write(busno, channels)? {
+            return Err("PCA9548 failed to ack control word")
+        }
+        stop(busno)?;
+        Ok(())
+    }
 }
 
 #[cfg(not(has_i2c))]
 mod imp {
     const NO_I2C: &'static str = "No I2C support on this platform";
-    pub fn init() {}
+    pub fn init() { Err(NO_I2C) }
     pub fn start(_busno: u8) -> Result<(), &'static str> { Err(NO_I2C) }
     pub fn restart(_busno: u8) -> Result<(), &'static str> { Err(NO_I2C) }
     pub fn stop(_busno: u8) -> Result<(), &'static str> { Err(NO_I2C) }
     pub fn write(_busno: u8, _data: u8) -> Result<bool, &'static str> { Err(NO_I2C) }
     pub fn read(_busno: u8, _ack: bool) -> Result<u8, &'static str> { Err(NO_I2C) }
+    pub fn pca9548_select(busno: u8, address: u8, channels: u8) -> Result<(), &'static str> { Err(NO_I2C) }
 }
 
 pub use self::imp::*;
diff --git a/artiq/firmware/libboard_artiq/i2c_eeprom.rs b/artiq/firmware/libboard_misoc/i2c_eeprom.rs
similarity index 91%
rename from artiq/firmware/libboard_artiq/i2c_eeprom.rs
rename to artiq/firmware/libboard_misoc/i2c_eeprom.rs
index e5f6cb9b3..0a15f7535 100644
--- a/artiq/firmware/libboard_artiq/i2c_eeprom.rs
+++ b/artiq/firmware/libboard_misoc/i2c_eeprom.rs
@@ -1,5 +1,4 @@
 use i2c;
-use pca9548;
 
 #[cfg(soc_platform = "kasli")]
 const I2C_SWITCH0: u8 = 0x70;
@@ -25,8 +24,8 @@ impl EEPROM {
 
     fn select(&self) -> Result<(), &'static str> {
         let mask: u16 = 1 << self.port;
-        pca9548::select(self.busno, I2C_SWITCH0, mask as u8)?;
-        pca9548::select(self.busno, I2C_SWITCH1, (mask >> 8) as u8)?;
+        i2c::pca9548_select(self.busno, I2C_SWITCH0, mask as u8)?;
+        i2c::pca9548_select(self.busno, I2C_SWITCH1, (mask >> 8) as u8)?;
 
         Ok(())
     }
diff --git a/artiq/firmware/libboard_misoc/lib.rs b/artiq/firmware/libboard_misoc/lib.rs
index 1b1b597d9..b49a69446 100644
--- a/artiq/firmware/libboard_misoc/lib.rs
+++ b/artiq/firmware/libboard_misoc/lib.rs
@@ -32,3 +32,8 @@ pub mod uart_console;
 pub mod uart_logger;
 #[cfg(all(has_ethmac, feature = "smoltcp"))]
 pub mod ethmac;
+pub mod i2c;
+#[cfg(soc_platform = "kasli")]
+pub mod i2c_eeprom;
+#[cfg(all(has_ethmac, feature = "smoltcp"))]
+pub mod net_settings;
diff --git a/artiq/firmware/runtime/net_settings.rs b/artiq/firmware/libboard_misoc/net_settings.rs
similarity index 51%
rename from artiq/firmware/runtime/net_settings.rs
rename to artiq/firmware/libboard_misoc/net_settings.rs
index d208479d5..3636c6924 100644
--- a/artiq/firmware/runtime/net_settings.rs
+++ b/artiq/firmware/libboard_misoc/net_settings.rs
@@ -1,8 +1,10 @@
+use core::fmt;
+
 use smoltcp::wire::{EthernetAddress, IpAddress};
 
-use board_misoc::config;
+use config;
 #[cfg(soc_platform = "kasli")]
-use board_artiq::i2c_eeprom;
+use i2c_eeprom;
 
 
 pub struct NetAddresses {
@@ -12,13 +14,22 @@ pub struct NetAddresses {
     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")?
+        }
+        Ok(())
+    }
+}
+
 pub fn get_adresses() -> NetAddresses {
     let hardware_addr;
     match config::read_str("mac", |r| r.map(|s| s.parse())) {
-        Ok(Ok(addr)) => {
-            hardware_addr = addr;
-            info!("using MAC address {}", hardware_addr);
-        }
+        Ok(Ok(addr)) => hardware_addr = addr,
         _ => {
             #[cfg(soc_platform = "kasli")]
             {
@@ -27,58 +38,34 @@ pub fn get_adresses() -> NetAddresses {
                     eeprom.read_eui48()
                     .map(|addr_buf| {
                         let hardware_addr = EthernetAddress(addr_buf);
-                        info!("using MAC address {} from EEPROM", hardware_addr);
                         hardware_addr
                     })
                     .unwrap_or_else(|e| {
-                        error!("failed to read MAC address from EEPROM: {}", e);
                         let hardware_addr = EthernetAddress([0x02, 0x00, 0x00, 0x00, 0x00, 0x21]);
-                        warn!("using default MAC address {}; consider changing it", hardware_addr);
                         hardware_addr
                     });
             }
             #[cfg(soc_platform = "sayma_amc")]
-            {
-                hardware_addr = EthernetAddress([0x02, 0x00, 0x00, 0x00, 0x00, 0x11]);
-                warn!("using default MAC address {}; consider changing it", hardware_addr);
-            }
+            { hardware_addr = EthernetAddress([0x02, 0x00, 0x00, 0x00, 0x00, 0x11]); }
             #[cfg(soc_platform = "metlino")]
-            {
-                hardware_addr = EthernetAddress([0x02, 0x00, 0x00, 0x00, 0x00, 0x19]);
-                warn!("using default MAC address {}; consider changing it", hardware_addr);
-            }
+            { hardware_addr = EthernetAddress([0x02, 0x00, 0x00, 0x00, 0x00, 0x19]); }
             #[cfg(soc_platform = "kc705")]
-            {
-                hardware_addr = EthernetAddress([0x02, 0x00, 0x00, 0x00, 0x00, 0x01]);
-                warn!("using default MAC address {}; consider changing it", hardware_addr);
-            }
+            { hardware_addr = EthernetAddress([0x02, 0x00, 0x00, 0x00, 0x00, 0x01]); }
         }
     }
 
     let ipv4_addr;
     match config::read_str("ip", |r| r.map(|s| s.parse())) {
-        Ok(Ok(addr)) => {
-            ipv4_addr = addr;
-            info!("using IPv4 address {}", ipv4_addr);
-        }
+        Ok(Ok(addr)) => ipv4_addr = addr,
         _ => {
             #[cfg(soc_platform = "kasli")]
-            {
-                ipv4_addr = IpAddress::v4(192, 168, 1, 70);
-            }
+            { ipv4_addr = IpAddress::v4(192, 168, 1, 70); }
             #[cfg(soc_platform = "sayma_amc")]
-            {
-                ipv4_addr = IpAddress::v4(192, 168, 1, 60);
-            }
+            { ipv4_addr = IpAddress::v4(192, 168, 1, 60); }
             #[cfg(soc_platform = "metlino")]
-            {
-                ipv4_addr = IpAddress::v4(192, 168, 1, 65);
-            }
+            { ipv4_addr = IpAddress::v4(192, 168, 1, 65); }
             #[cfg(soc_platform = "kc705")]
-            {
-                ipv4_addr = IpAddress::v4(192, 168, 1, 50);
-            }
-            info!("using default IPv4 address {}", ipv4_addr);
+            { ipv4_addr = IpAddress::v4(192, 168, 1, 50); }
         }
     }
 
@@ -88,17 +75,10 @@ pub fn get_adresses() -> NetAddresses {
         ((hardware_addr.0[2] as u16) << 8) | 0x00ff,
         0xfe00 | (hardware_addr.0[3] as u16),
         ((hardware_addr.0[4] as u16) << 8) | (hardware_addr.0[5] as u16));
-    info!("using IPv6 link-local address {}", ipv6_ll_addr);
 
     let ipv6_addr = match config::read_str("ip6", |r| r.map(|s| s.parse())) {
-        Ok(Ok(addr)) => {
-            info!("using IPv6 configured address {}", addr);
-            Some(addr)
-        },
-        _ => {
-            info!("no IPv6 configured address");
-            None
-        }
+        Ok(Ok(addr)) => Some(addr),
+        _ => None
     };
 
     NetAddresses {
diff --git a/artiq/firmware/runtime/kern_hwreq.rs b/artiq/firmware/runtime/kern_hwreq.rs
index d039d7ce2..53e0daa8a 100644
--- a/artiq/firmware/runtime/kern_hwreq.rs
+++ b/artiq/firmware/runtime/kern_hwreq.rs
@@ -4,8 +4,8 @@ use sched::{Io, Mutex, Error as SchedError};
 use session::{kern_acknowledge, kern_send, Error};
 use rtio_mgt;
 use urc::Urc;
+use board_misoc::i2c as local_i2c;
 use board_artiq::drtio_routing;
-use board_artiq::i2c as local_i2c;
 use board_artiq::spi as local_spi;
 
 #[cfg(has_drtio)]
diff --git a/artiq/firmware/runtime/main.rs b/artiq/firmware/runtime/main.rs
index 8d39f4001..0f24877d8 100644
--- a/artiq/firmware/runtime/main.rs
+++ b/artiq/firmware/runtime/main.rs
@@ -30,7 +30,7 @@ use core::cell::RefCell;
 use core::convert::TryFrom;
 use smoltcp::wire::IpCidr;
 
-use board_misoc::{csr, irq, ident, clock, boot, config};
+use board_misoc::{csr, irq, ident, clock, boot, config, net_settings};
 #[cfg(has_ethmac)]
 use board_misoc::ethmac;
 #[cfg(has_drtio)]
@@ -41,8 +41,6 @@ use proto_artiq::{mgmt_proto, moninj_proto, rpc_proto, session_proto, kernel_pro
 #[cfg(has_rtio_analyzer)]
 use proto_artiq::analyzer_proto;
 
-mod net_settings;
-
 mod rtio_clocking;
 mod rtio_mgt;
 
@@ -122,7 +120,7 @@ fn startup() {
 
     setup_log_levels();
     #[cfg(has_i2c)]
-    board_artiq::i2c::init();
+    board_misoc::i2c::init().expect("I2C initialization failed");
     sayma_hw_init();
     rtio_clocking::init();
 
@@ -152,6 +150,7 @@ fn startup() {
     let neighbor_cache =
         smoltcp::iface::NeighborCache::new(alloc::btree_map::BTreeMap::new());
     let net_addresses = net_settings::get_adresses();
+    info!("network addresses: {}", net_addresses);
     let mut interface = match net_addresses.ipv6_addr {
         Some(addr) => {
             let ip_addrs = [
diff --git a/artiq/firmware/satman/main.rs b/artiq/firmware/satman/main.rs
index ce0d92ae4..98cc844c9 100644
--- a/artiq/firmware/satman/main.rs
+++ b/artiq/firmware/satman/main.rs
@@ -8,8 +8,8 @@ extern crate board_misoc;
 extern crate board_artiq;
 
 use core::convert::TryFrom;
-use board_misoc::{csr, irq, ident, clock, uart_logger};
-use board_artiq::{i2c, spi, si5324, drtioaux};
+use board_misoc::{csr, irq, ident, clock, uart_logger, i2c};
+use board_artiq::{spi, si5324, drtioaux};
 use board_artiq::drtio_routing;
 #[cfg(has_hmc830_7043)]
 use board_artiq::hmc830_7043;
@@ -451,7 +451,7 @@ pub extern fn main() -> i32 {
     #[cfg(has_slave_fpga_cfg)]
     board_artiq::slave_fpga::load().expect("cannot load RTM FPGA gateware");
 
-    i2c::init();
+    i2c::init().expect("I2C initialization failed");
     si5324::setup(&SI5324_SETTINGS, si5324::Input::Ckin1).expect("cannot initialize Si5324");
     unsafe {
         csr::drtio_transceiver::stable_clkin_write(1);