diff --git a/artiq/firmware/libboard_artiq/serwb.rs b/artiq/firmware/libboard_artiq/serwb.rs
index e00f3395a..7f9d750a0 100644
--- a/artiq/firmware/libboard_artiq/serwb.rs
+++ b/artiq/firmware/libboard_artiq/serwb.rs
@@ -1,53 +1,71 @@
 use core::{cmp, str};
 use board_misoc::{csr, clock};
 
-fn read_rtm_ident(buf: &mut [u8]) -> &str {
-    unsafe {
-        csr::rtm_identifier::address_write(0);
-        let len = csr::rtm_identifier::data_read();
-        let len = cmp::min(len, buf.len() as u8);
-        for i in 0..len {
-            csr::rtm_identifier::address_write(1 + i);
-            buf[i as usize] = csr::rtm_identifier::data_read();
-        }
-        str::from_utf8_unchecked(&buf[..len as usize])
-    }
-}
-
-unsafe fn debug_print(rtm: bool) {
-    info!("AMC serwb settings:");
-    info!("  bitslip: {}", csr::serwb_phy_amc::control_bitslip_read());
-    info!("  ready: {}", csr::serwb_phy_amc::control_ready_read());
-    info!("  error: {}", csr::serwb_phy_amc::control_error_read());
+fn debug_print(rtm: bool) {
+    debug!("AMC serwb settings:");
+    debug!("  bitslip: {}", unsafe { csr::serwb_phy_amc::control_bitslip_read() });
+    debug!("  ready: {}", unsafe { csr::serwb_phy_amc::control_ready_read() });
+    debug!("  error: {}", unsafe { csr::serwb_phy_amc::control_error_read() });
 
     if rtm {
-        info!("RTM serwb settings:");
-        info!("  bitslip: {}", csr::serwb_phy_rtm::control_bitslip_read());
-        info!("  ready: {}", csr::serwb_phy_rtm::control_ready_read());
-        info!("  error: {}", csr::serwb_phy_rtm::control_error_read());
+        debug!("RTM serwb settings:");
+        debug!("  bitslip: {}", unsafe { csr::serwb_phy_rtm::control_bitslip_read() });
+        debug!("  ready: {}", unsafe { csr::serwb_phy_rtm::control_ready_read() });
+        debug!("  error: {}", unsafe { csr::serwb_phy_rtm::control_error_read() });
     }
 }
 
 fn prbs_test() {
     let prbs_test_cycles : u32 = 1<<22;
-    let prbs_test_us : u64 = ((prbs_test_cycles as u64)*40)/125; // 40 bits @125MHz linerate
+    // 40 bits @125MHz linerate
+    let prbs_test_us : u64 = ((prbs_test_cycles as u64)*40)/125;
 
+    info!("RTM to AMC link test...");
     unsafe {
-        info!("RTM to AMC Link test");
         csr::serwb_phy_amc::control_prbs_cycles_write(prbs_test_cycles);
         csr::serwb_phy_amc::control_prbs_start_write(1);
-        clock::spin_us(prbs_test_us*110/100); // PRBS test time + 10%
-        info!("{} errors", csr::serwb_phy_amc::control_prbs_errors_read());
+    }
+    clock::spin_us(prbs_test_us*110/100); // PRBS test time + 10%
+    let errors = unsafe {
+        csr::serwb_phy_amc::control_prbs_errors_read()
+    };
+    if errors == 0 {
+        info!("  ...passed")
+    } else {
+        error!("  {} errors found", errors);
+    }
 
-        info!("AMC to RTM Link test");
+    info!("AMC to RTM link test...");
+    unsafe {
         csr::serwb_phy_rtm::control_prbs_cycles_write(prbs_test_cycles);
         csr::serwb_phy_rtm::control_prbs_start_write(1);
-        clock::spin_us(prbs_test_us*110/100); // PRBS test time + 10%
-        info!("{} errors", csr::serwb_phy_rtm::control_prbs_errors_read());
+    }
+    clock::spin_us(prbs_test_us*110/100); // PRBS test time + 10%
+    let errors = unsafe {
+        csr::serwb_phy_rtm::control_prbs_errors_read()
+    };
+    if errors == 0 {
+        info!("  ...passed");
+    } else {
+        error!("  {} errors found", errors);
     }
 }
 
-fn prng32(seed: &mut u32) -> u32 { *seed = 1664525 * *seed + 1013904223; *seed }
+fn magic_test() {
+    // Try reading the magic number register on the other side of the bridge.
+    let rtm_magic = unsafe {
+        csr::rtm_magic::magic_read()
+    };
+    if rtm_magic != 0x5352544d {
+        error!("incorrect RTM magic number: 0x{:08x}", rtm_magic);
+        // proceed anyway
+    }
+}
+
+fn prng32(seed: &mut u32) -> u32 {
+    *seed = 1664525 * *seed + 1013904223;
+    *seed
+}
 
 fn wishbone_test() {
     let test_length: u32 = 512;
@@ -76,7 +94,24 @@ fn wishbone_test() {
             }
         }
     }
-    info!("{} errors", test_errors);
+    if test_errors == 0 {
+        info!("  ...passed");
+    } else {
+        error!("  {} errors found", test_errors);
+    }
+}
+
+fn read_rtm_ident(buf: &mut [u8]) -> &str {
+    unsafe {
+        csr::rtm_identifier::address_write(0);
+        let len = csr::rtm_identifier::data_read();
+        let len = cmp::min(len, buf.len() as u8);
+        for i in 0..len {
+            csr::rtm_identifier::address_write(1 + i);
+            buf[i as usize] = csr::rtm_identifier::data_read();
+        }
+        str::from_utf8_unchecked(&buf[..len as usize])
+    }
 }
 
 pub fn wait_init() {
@@ -91,26 +126,13 @@ pub fn wait_init() {
             }
         }
     }
-    info!("done.");
+    info!(" ...done.");
 
-    // PRBS test
     prbs_test();
-
-    // Wishbone test
+    magic_test();
     wishbone_test();
 
-    // Try reading the magic number register on the other side of the bridge.
-    let rtm_magic = unsafe {
-        csr::rtm_magic::magic_read()
-    };
-    if rtm_magic != 0x5352544d {
-        error!("incorrect RTM magic number: 0x{:08x}", rtm_magic);
-        // proceed anyway
-    }
-
-    unsafe {
-        debug_print(true);
-    }
+    debug_print(true);
 
     info!("RTM gateware version {}", read_rtm_ident(&mut [0; 64]));
 }