diff --git a/gex/Client.py b/gex/Client.py
index 7a08e69..27d4ecf 100644
--- a/gex/Client.py
+++ b/gex/Client.py
@@ -152,7 +152,36 @@ class Client:
         return buffer
 
     def bulk_write(self, cs, cmd, bulk, id=None, pld=None):
-        """ Perform a bulk write. If cs is None, cmd is used as message type """
+        """
+        Perform a bulk write. If cs is None, cmd is used as message type.
+        bulk is the data to write.
+        """
 
+        offer = self.query(cs=cs, cmd=cmd, id=id, pld=pld)
+        if offer.type != gex.MSG_BULK_WRITE_OFFER:
+            raise Exception("Bulk write rejected! %s" % offer.data.decode('utf-8'))
+
+        # parse the offer
+        pp = PayloadParser(offer.data)
+        max_size = pp.u32()
+        max_chunk = pp.u32()
+
+        total = len(bulk)
+
+        if max_size < total:
+            # announce we changed our mind and won't write anything
+            self.send_raw(type=gex.MSG_BULK_ABORT, id=offer.id)
+            raise Exception("Bulk write not possible, not enough space (needed %d bytes, max %d)" % (total, max_size))
+
+        at = 0
+        while at < total:
+            chunklen = min(max_chunk, total - at)
+            # Send data
+            rv = self.query_raw(type=gex.MSG_BULK_DATA if chunklen == max_chunk else gex.MSG_BULK_END,
+                                id=offer.id,
+                                pld=bulk[at:at+chunklen])
 
+            if rv.type != gex.MSG_SUCCESS:
+                raise Exception("Unexpected bulk frame type %d" % rv.type)
 
+            at += chunklen
diff --git a/main.py b/main.py
index daf3bca..c0b432d 100644
--- a/main.py
+++ b/main.py
@@ -8,6 +8,8 @@ client = gex.Client()
 buf = client.bulk_read(None, gex.MSG_INI_READ)
 print(buf.decode('utf-8'))
 
+client.bulk_write(None, gex.MSG_INI_WRITE, buf)
+
 if False:
     led = gex.Pin(client, 'LED')