How did this ever work properly before?

src/core/debug.c

 }
 
 /* Produce a paged hex dump of the specified data and length */
-void hex_dump ( const char *data, const unsigned int len ) {
+void hex_dump ( const unsigned char *data, const unsigned int len ) {
 	unsigned int index;
 	for ( index = 0; index < len; index++ ) {
 		if ( ( index % 16 ) == 0 ) {