diff --git a/artiq/devices/lda/driver.py b/artiq/devices/lda/driver.py
index 2e422c2ab..c95dcd395 100644
--- a/artiq/devices/lda/driver.py
+++ b/artiq/devices/lda/driver.py
@@ -159,4 +159,4 @@ class Lda:
         :type attenuation: int, float or Fraction
 
         """
-        self.set(0x8d, bytes(chr(int(round(attenuation*4))), "latin_1"))
+        self.set(0x8d, bytes([int(round(attenuation*4))]))