diff --git a/buffer.py b/buffer.py
index 06418ef..6718f95 100644
--- a/buffer.py
+++ b/buffer.py
@@ -523,10 +523,37 @@ class Binary32Buffer(FileBuffer):
     def __init__(self, path, nl='\n', name=None):
         '''fb = FileBuffer(path)'''
         FileBuffer.__init__(self, path, nl, name)
+    def cursorx_to_datax(self, cx):
+        if cx >= 0 and cx < 8:
+            return cx // 2
+        elif cx >= 9 and cx < 17:
+            return (cx - 1) // 2
+        elif cx >= 18 and cx < 26:
+            return (cx - 2) // 2
+        elif cx >= 27 and cx < 35:
+            return (cx - 3) // 2
+        else:
+            return None
+    def datax_to_cursorx(self, ix):
+        if ix >= 0 and ix < 4:
+            return ix * 2
+        elif ix >= 4 and ix < 8:
+            return ix * 2 + 1
+        elif ix >= 8 and ix < 12:
+            return ix * 2 + 2
+        elif ix >= 12 and ix < 16:
+            return ix * 2 + 3
+        else:
+            return None
     def overwrite_char(self, p, c, act=ACT_NORM, force=False):
+        ix = self.cursorx_to_datax(p.x)
+        if ix is None:
+            return
         Buffer.overwrite_char(self, p, c, act, force)
+        cx = self.datax_to_cursorx(ix)
+        c = chr(int(self.lines[p.y][cx:cx + 2], 16))
         rawline = self.rawdata[p.y]
-        self.rawdata[p.y] = rawline[0:p.x] + c + rawline[p.x + 1:]
+        self.rawdata[p.y] = rawline[0:ix] + c + rawline[ix + 1:]
     def read_filter(self, data):
         self.rawdata = []
         lines = []
diff --git a/mode/hex.py b/mode/hex.py
index 0c96f53..d5bfc67 100644
--- a/mode/hex.py
+++ b/mode/hex.py
@@ -50,21 +50,13 @@ class Hex(mode.Fundamental):
             (cx, cy) = self.window.cursor.xy()
             s = string.translate(self.window.buffer.rawdata[y], self.ctrans)
             if cy == y:
-                i = None
-                if cx >= 0 and cx < 8:
-                    i = cx // 2
-                elif cx >= 9 and cx < 17:
-                    i = (cx - 1) // 2
-                elif cx >= 18 and cx < 26:
-                    i = (cx - 2) // 2
-                elif cx >= 27 and cx < 35:
-                    i = (cx - 3) // 2
-                if i is not None:
-                    return ((0, s[0:i], color.build('green', 'default', 'bold')),
-                            (0, s[i], color.build('green', 'default', 'bold', 'reverse')),
-                            (0, s[i+1:], color.build('green', 'default', 'bold')))
-                else:
+                i = self.window.buffer.cursorx_to_datax(cx)
+                if i is None:
                     return ((0, s, color.build('green', 'default', 'bold')),)
+                else:
+                    return ((0, s[0:i], color.build('green', 'default', 'bold')),
+                            (i, s[i], color.build('default', 'default', 'bold', 'reverse')),
+                            (i + 1, s[i+1:], color.build('green', 'default', 'bold')))
             else:
                 return ((0, s, color.build('green', 'default', 'bold')),)