diff --git a/artiq/firmware/libboard/build.rs b/artiq/firmware/libboard/build.rs
index 26a3aa1bc..03ad582f8 100644
--- a/artiq/firmware/libboard/build.rs
+++ b/artiq/firmware/libboard/build.rs
@@ -8,12 +8,12 @@ use std::process::Command;
 
 fn gen_hmc7043_writes() {
     println!("cargo:rerun-if-changed=hmc7043_gen_writes.py");
-    println!("cargo:rerun-if-changed=hmc7043_guiexport_10gbps.py");
+    println!("cargo:rerun-if-changed=hmc7043_guiexport_6gbps.py");
 
     let hmc7043_writes =
         Command::new("python3")
                 .arg("hmc7043_gen_writes.py")
-                .arg("hmc7043_guiexport_10gbps.py")
+                .arg("hmc7043_guiexport_6gbps.py")
                 .output()
                 .ok()
                 .and_then(|o| String::from_utf8(o.stdout).ok())
diff --git a/artiq/firmware/libboard/hmc7043_guiexport_10gbps.py b/artiq/firmware/libboard/hmc7043_guiexport_6gbps.py
similarity index 99%
rename from artiq/firmware/libboard/hmc7043_guiexport_10gbps.py
rename to artiq/firmware/libboard/hmc7043_guiexport_6gbps.py
index de3275ba0..77841ea03 100644
--- a/artiq/firmware/libboard/hmc7043_guiexport_10gbps.py
+++ b/artiq/firmware/libboard/hmc7043_guiexport_6gbps.py
@@ -315,14 +315,14 @@ dut.write(0xED, 0x0)
 # clkgrp2_div2_cfg2_mutesel[7:6] = 0x0
 dut.write(0xEE, 0x9)
 
-# clkgrp3_div1_cfg1_en[0:0] = 0x0
+# clkgrp3_div1_cfg1_en[0:0] = 0x1
 # clkgrp3_div1_cfg1_phdelta_mslip[1:1] = 0x1
 # clkgrp3_div1_cfg2_startmode[3:2] = 0x0
 # clkgrp3_div1_cfg1_rev[4:4] = 0x1
 # clkgrp3_div1_cfg1_slipmask[5:5] = 0x1
 # clkgrp3_div1_cfg1_reseedmask[6:6] = 0x1
 # clkgrp3_div1_cfg1_hi_perf[7:7] = 0x0
-dut.write(0xF0, 0x72)
+dut.write(0xF0, 0x73)
 
 # clkgrp3_div1_cfg12_divrat_lsb[7:0] = 0x2
 dut.write(0xF1, 0x2)
@@ -693,5 +693,4 @@ dut.write(0x151, 0x0)
 # clkgrp7_div2_cfg5_drvr_mode[4:3] = 0x1
 # clkgrp7_div2_cfg_outbuf_dyn[5:5] = 0x0
 # clkgrp7_div2_cfg2_mutesel[7:6] = 0x0
-dut.write(0x152, 0xB)
-
+dut.write(0x152, 0xB)
\ No newline at end of file
diff --git a/artiq/firmware/libboard/hmc830_7043.rs b/artiq/firmware/libboard/hmc830_7043.rs
index 865d09233..bdd60360a 100644
--- a/artiq/firmware/libboard/hmc830_7043.rs
+++ b/artiq/firmware/libboard/hmc830_7043.rs
@@ -1,15 +1,32 @@
 /*
  * HMC830 config:
- * 100MHz input, 1GHz output
+ * 100MHz input, 1.2GHz output
  * fvco = (refclk / r_divider) * n_divider
  * fout = fvco/2
  *
  * HMC7043 config:
- * dac clock: 1GHz (div=1)
- * fpga clock: 250MHz (div=4)
- * sysref clock: 15.625MHz (div=64)
+ * dac clock: 600MHz (div=1)
+ * fpga clock: 150MHz (div=4)
+ * sysref clock: 9.375MHz (div=64)
  */
 
+mod clock_mux {
+    use csr;
+
+    const CLK_SRC_EXT_SEL : u8 = 1 << 0;
+    const REF_CLK_SRC_SEL : u8 = 1 << 1;
+    const DAC_CLK_SRC_SEL : u8 = 1 << 2;
+
+    pub fn init() -> Result<(), &'static str> {
+        unsafe {
+            csr::clock_mux::out_write(
+                1*CLK_SRC_EXT_SEL |  // use ext clk from sma
+                1*REF_CLK_SRC_SEL |  //
+                0*DAC_CLK_SRC_SEL);  // use clk from dac_clk // FIXME (should use hmc830 output)
+        }
+        Ok(())
+    }
+}
 
 mod hmc830 {
     use clock;
@@ -31,7 +48,7 @@ mod hmc830 {
         (0xa, 0x2046),
         (0xb, 0x7c061),
         (0xf, 0x81),
-        (0x3, 0x28), // n_divider
+        (0x3, 0x30), // n_divider
     ];
 
     fn spi_setup() {
@@ -90,11 +107,11 @@ mod hmc830 {
 
         let t = clock::get_ms();
         info!("HMC830 waiting for lock...");
-        //while read(0x12) & 0x02 == 0 {
-        //    if clock::get_ms() > t + 2000 {
-        //        return Err("HMC830 lock timeout");
-        //    }
-        //}
+        while read(0x12) & 0x02 == 0 {
+            if clock::get_ms() > t + 2000 {
+                return Err("HMC830 lock timeout");
+            }
+        }
 
         Ok(())
     }
@@ -163,6 +180,7 @@ mod hmc7043 {
 }
 
 pub fn init() -> Result<(), &'static str> {
+    clock_mux::init();
     hmc830::init()?;
     hmc7043::init()
 }