-are going to use: <code>chmod 666 /dev/<devicename><code>
-<!--
-<li> Add any users who will be using TinyOS to the uucp, lp, and lock
-groups: </li>
--->
-</code></code></li></ol>
-
-</li></ul>
-<a name="tinyos1"><h1>Switching back to a TinyOS 1.x tree</h1></a>
-Since the tools are backwardly compatible, you need only change
+are going to use: <code>chmod 666 /dev/<devicename></code></li>
+</ol></li>
+</ul>
+
+<ul>
+<li><p>Finally, if you have installed TinyOS 2.0.1, there is a bug in TOSSIM (which will be fixed in 2.0.2).
+The bug is in file <tt>tos/chips/atm128/sim/atm128_sim.h</tt>. Change these lines 22 and 23 from:</p>
+
+<pre>
+#define _SFR_IO8(io_addr) _MMIO_BYTE((io_addr) + 0x20)
+#define _SFR_IO16(io_addr) _MMIO_WORD((io_addr) + 0x20)
+</pre>
+
+<p>to</p>
+
+<pre>
+#define _SFR_IO8(io_addr) _MMIO_BYTE((io_addr))
+#define _SFR_IO16(io_addr) _MMIO_WORD((io_addr))
+</pre>
+
+<p>If you do not do this, then timers will not work correctly.</p>
+</li>
+</ul>
+
+<h1><a name="tinyos1">Switching back to a TinyOS 1.x tree</a></h1>
+<p>Since the tools are backwardly compatible, you need only change