diff --git a/artiq/firmware/libboard_artiq/hmc830_7043.rs b/artiq/firmware/libboard_artiq/hmc830_7043.rs
index 2897aa92d..757f2b7df 100644
--- a/artiq/firmware/libboard_artiq/hmc830_7043.rs
+++ b/artiq/firmware/libboard_artiq/hmc830_7043.rs
@@ -263,7 +263,8 @@ pub mod hmc7043 {
         spi_setup();
         info!("loading configuration...");
 
-        write(0xA, 0x06);  // Disable the REFSYNCIN input
+        write(0x3, 0x14);  // Disable the REFSYNCIN reseeder
+        write(0xA, 0x06);  // Disable the REFSYNCIN input buffer
         write(0xB, 0x07);  // Enable the CLKIN input as LVPECL
         write(0x50, 0x1f); // Disable GPO pin
         write(0x9F, 0x4d); // Unexplained high-performance mode