diff -r 5a17f1c24b38 -r bd48c6dd24d3 chirp/h777.py
--- a/chirp/h777.py	Sun Feb 01 17:51:08 2015 -0500
+++ b/chirp/h777.py	Fri Feb 06 19:24:47 2015 +0100
@@ -254,6 +254,7 @@
         rf.valid_modes = ["NFM", "FM"]  # 12.5 KHz, 25 kHz.
         rf.valid_skips = ["", "S"]
         rf.valid_tmodes = ["", "Tone", "TSQL", "DTCS", "Cross"]
+        rf.valid_duplexes = ["", "-", "+", "off"]
         rf.has_rx_dtcs = True
         rf.has_ctone = True
         rf.has_cross = True
@@ -329,7 +330,10 @@
             mem.empty = True
             return mem
 
-        if int(_mem.rxfreq) == int(_mem.txfreq):
+        if _mem.txfreq.get_raw() == "\xFF\xFF\xFF\xFF":
+            mem.duplex = "off"
+            mem.offset = 0
+        elif int(_mem.rxfreq) == int(_mem.txfreq):
             mem.duplex = ""
             mem.offset = 0
         else:
@@ -353,6 +357,13 @@
                           RadioSettingValueBoolean(not _mem.beatshift))
         mem.extra.append(rs)
 
+        # When set to one, official programming software (BF-480) shows always
+        # "WFM", even if we choose "NFM". Therefore, for compatibility
+        # purposes, we will set these to zero.
+        mem.unknown1 = 0;
+        mem.unknown2 = 0;
+        mem.unknown3 = 0;
+
         return mem
 
     def set_memory(self, mem):