diff --git a/artiq/firmware/libboard/lib.rs b/artiq/firmware/libboard/lib.rs
index d31c9e4e2..6c08c4464 100644
--- a/artiq/firmware/libboard/lib.rs
+++ b/artiq/firmware/libboard/lib.rs
@@ -5,7 +5,7 @@ extern crate byteorder;
 #[macro_use]
 extern crate log;
 
-use core::{cmp, ptr, str};
+use core::{cmp, str};
 
 include!(concat!(env!("BUILDINC_DIRECTORY"), "/generated/mem.rs"));
 include!(concat!(env!("BUILDINC_DIRECTORY"), "/generated/csr.rs"));
@@ -45,11 +45,13 @@ pub use uart_console::Console;
 
 pub fn ident(buf: &mut [u8]) -> &str {
     unsafe {
-        let len = ptr::read_volatile(csr::IDENTIFIER_MEM_BASE);
-        let len = cmp::min(len as usize, buf.len());
+        csr::identifier::address_write(0);
+        let len = csr::identifier::data_read();
+        let len = cmp::min(len, buf.len() as u8);
         for i in 0..len {
-            buf[i] = ptr::read_volatile(csr::IDENTIFIER_MEM_BASE.offset(1 + i as isize)) as u8
+            csr::identifier::address_write(1 + i);
+            buf[i as usize] = csr::identifier::data_read();
         }
-        str::from_utf8_unchecked(&buf[..len])
+        str::from_utf8_unchecked(&buf[..len as usize])
     }
 }