Updated README with two known bugs,

README.rst

@@ -39,3 +39,11 @@ Bug reporting
 -------------
 
 Please use the GitHub system to report feature request and bugs.
+
+Known issues
+------------
+
+CMTS and CM MIC are have the wrong value when calculated on a big endian CPU. Using the MIC values and a big endian CPU should be avoided in production systems.
+
+Quoting the hex strings will result in a crash. Do not use something similar to "0xABCD".
+