diff --git a/artiq/gateware/targets/sayma_rtm.py b/artiq/gateware/targets/sayma_rtm.py
index b4401e9e0..7fa740381 100755
--- a/artiq/gateware/targets/sayma_rtm.py
+++ b/artiq/gateware/targets/sayma_rtm.py
@@ -240,7 +240,7 @@ class SatmanSoCBuilder(Builder):
                               "satman.bin")
         with open(satman, "rb") as boot_file:
             boot_data = []
-            unpack_endian = ">I"
+            unpack_endian = "<I"
             while True:
                 w = boot_file.read(4)
                 if not w: