idevicebackup2 fails with iOS 5.0.1/iPad2 - plist parsing error ?

After investigating the whole stack (libplist, libxml2), it seems that the XML is indeed invalid.
patching libxml2 as follows would temporarily fix it

diff --git a/parser.c b/parser.c
index 72a467c..a501cdb 100644
--- a/parser.c
+++ b/parser.c
@@ -4431,9 +4431,9 @@ xmlParseCharDataComplex(xmlParserCtxtPtr ctxt, int cdata) {
     }
     if ((cur != 0) && (!IS_CHAR(cur))) {
        /* Generate the error and skip the offending character */
-        xmlFatalErrMsgInt(ctxt, XML_ERR_INVALID_CHAR,
-                          "PCDATA invalid Char value %d\n",
-                         cur);
+               // xmlFatalErrMsgInt(ctxt, XML_ERR_INVALID_CHAR,
+               //                 "PCDATA invalid Char value %d\n",
+       //               cur);
        NEXTL(l);
     }
 }