fix Python init header generation

litedram/init.py

@@ -627,10 +627,10 @@ def get_sdram_phy_py_header(phy_settings, timing_settings):
     r += "dfii_command_rddata = 0x20\n"
     r += "\n"
 
-    init_sequence, mr1 = get_sdram_phy_init_sequence(phy_settings, timing_settings)
+    init_sequence, mr = get_sdram_phy_init_sequence(phy_settings, timing_settings)
 
-    if mr1 is not None:
-        r += "ddrx_mr1 = 0x{:x}\n".format(mr1)
+    if mr is not None and 1 in mr:
+        r += "ddrx_mr1 = 0x{:x}\n".format(mr[1])
         r += "\n"
 
     r += "init_sequence = [\n"