diff --git a/fhem/FHEM/99_updatefhem.pm b/fhem/FHEM/99_updatefhem.pm
index 751a25e17..55bbb3e92 100644
--- a/fhem/FHEM/99_updatefhem.pm
+++ b/fhem/FHEM/99_updatefhem.pm
@@ -4,19 +4,25 @@ use warnings;
 use IO::Socket;
 
 sub CommandUpdatefhem($$);
+sub CommandCULflash($$);
 
 my $server = "fhem.de:80";
 my $sdir   = "/fhemupdate";
 my $ftime  = "filetimes.txt";
+my $dfu    = "dfu-programmer";
 
 
 #####################################
 sub
 updatefhem_Initialize($$)
 {
-  my %lhash = ( Fn=>"CommandUpdatefhem",
-                Hlp=>",update fhem from the nightly CVS checkout" );
-  $cmds{updatefhem} = \%lhash;
+  my %fhash = ( Fn=>"CommandUpdatefhem",
+                Hlp=>",update fhem from the nightly CVS" );
+  $cmds{updatefhem} = \%fhash;
+
+  my %chash = ( Fn=>"CommandCULflash",
+                Hlp=>"<cul> <type>,flash the CUL from the nightly CVS" );
+  $cmds{CULflash} = \%chash;
 }
 
 
@@ -27,7 +33,6 @@ CommandUpdatefhem($$)
   my ($cl, $param) = @_;
   my $lt = "";
   my $ret = "";
-
   #my $moddir = "$attr{global}{modpath}/FHEM";
   my $moddir = "XXX";
 
@@ -62,6 +67,7 @@ CommandUpdatefhem($$)
       next if($f ne $param);
     } else {
       next if($oldtime{$f} && $filetime{$f} eq $oldtime{$f});
+      next if($f =~ m/.hex$/);  # skip firmware files
     }
     my $localfile = "$moddir/$f";
     my $remfile = $f;
@@ -101,6 +107,68 @@ CommandUpdatefhem($$)
   return $ret;
 }
 
+sub
+CommandCULflash($$)
+{
+  my ($cl, $param) = @_;
+  #my $moddir = "$attr{global}{modpath}/FHEM";
+  my $moddir = "XXX";
+
+  my %ctypes = (
+    CUL_V2     => "at90usb162",
+    CUL_V2_HM  => "at90usb162",
+    CUL_V3     => "atmega32u4",
+    CUL_V4     => "atmega32u2",
+  );
+  my @a = split("[ \t]+", $param);
+  return "Usage: CULflash <Fhem-CUL-Device> <CUL-type>, ".
+                "where <CUL-type> is one of ". join(" ", sort keys %ctypes)
+      if(int(@a) != 2 ||
+         !$defs{$a[0]} ||
+         $defs{$a[0]}{TYPE} ne "CUL" ||
+         !$ctypes{$a[1]});
+
+  my $cul  = $a[0];
+  my $target = $a[1];
+
+  ################################
+  # First get the index file to prove the file size
+  my $filetimes = GetHttpFile($server, "$sdir/$ftime");
+  return "Can't get $ftime from $server" if(!$filetimes);
+
+  my (%filetime, %filesize);
+  foreach my $l (split("[\r\n]", $filetimes)) {
+    chomp($l);
+    return "Corrupted filetimes.txt file"
+        if($l !~ m/^20\d\d-\d\d-\d\d_\d\d:\d\d:\d\d /);
+    my ($ts, $fs, $file) = split(" ", $l, 3);
+    $filetime{$file} = $ts;
+    $filesize{$file} = $fs;
+  }
+
+  ################################
+  # Now get the firmware file:
+  my $content = GetHttpFile($server, "$sdir/$target.hex");
+  return "File size for $target.hex does not correspond to filetimes.txt entry"
+          if(length($content) ne $filesize{"$target.hex"});
+  my $localfile = "$moddir/$target.hex";
+  open(FH,">$localfile") || return "Can't write $localfile";
+  print FH $content;
+  close(FH);
+
+  my $cmd = "($dfu MCU erase && $dfu MCU flash TARGET && $dfu MCU start) 2>&1";
+  my $mcu = $ctypes{$target};
+  $cmd =~ s/MCU/$mcu/g;
+  $cmd =~ s/TARGET/$localfile/g;
+
+  CUL_SimpleWrite($defs{CUL}, "B01");
+  sleep(4);     # B01 needs 2 seconds for the reset
+  Log 1, $cmd;
+  my $result = `$cmd`;
+  Log 1, $result;
+  return $result;
+}
+
 sub
 GetHttpFile($$)
 {
diff --git a/fhem/docs/commandref.html b/fhem/docs/commandref.html
index bb1e78074..703552176 100644
--- a/fhem/docs/commandref.html
+++ b/fhem/docs/commandref.html
@@ -38,6 +38,7 @@
   <ul>
 
       <a href="#attr">attr</a> &nbsp;
+      <a href="#CULflash">CULflash</a> &nbsp;
       <a href="#define">define</a> &nbsp;
       <a href="#delete">delete</a> &nbsp;
       <a href="#deleteattr">deleteattr</a> &nbsp;
@@ -534,15 +535,36 @@ A line ending with \ will be concatenated with the next one, so long lines
   <code>updatefhem [filename]</code> <br>
   <br>
     Update the fhem modules and documentation from a nightly CVS chekout.  For
-    this purpose fhem contants http://fhem.de, compares the stored timestamps
-    of the local files with the filelist on the server, and downloads the files
-    changed on the server. For all downloaded modules a reload will be
-    scheduled if the corresponding module is loaded.<br>
+    this purpose fhem contacts http://fhem.de/fhemupdate, compares the stored
+    timestamps of the local files with the filelist on the server, and
+    downloads the files changed on the server. For all downloaded modules a
+    reload will be scheduled if the corresponding module is loaded.<br>
     If an explicit filename is given, then this file will be downloaded
     unconditionally.<br>
     Note: if the main program (fhem.pl) is changed, a manual restart of fhem
     will be necessary to apply the changes.
-    <br> </ul>
+    <br>
+</ul>
+
+<a name="CULflash"></a>
+<h3>CULflash</h3>
+<ul>
+  <code>CULflash &lt;CUL-Name&gt; &lt;CUL-Version&gt;</code> <br>
+  <br>
+    Download the CUL firmware from a nightly CVS chekout and flash the
+    hardware. Currently only the CUL is supported with its versions:
+    CUL_V2, CUL_V2_HM, CUL_V3, CUL_V4.<br>
+    <b>Note:</b> dfu-programmer has to be installed in the path.<br>
+    If the CUL is not yet flashed, then first define a <a href="#CUL">CUL</a>
+    device (even if fhem won't be able to open the device), insert it with the
+    button pressed (this will set the device into flash-mode), then issue the
+    CULflash command.<br>
+    Example:
+    <ul>
+    <code>fhem> CULflash CUL CUL_V3</code>
+    </ul>
+</ul>
+
 
 <a name="list"></a>
 <h3>list</h3>