diff --git a/asm.cpp b/asm.cpp
index a0292d4..078ec69 100644
--- a/asm.cpp
+++ b/asm.cpp
@@ -1357,7 +1357,6 @@ void CLASS::initpass(void)
 	s = Poco::trim(Poco::toUpper(s));
 
 	cpumode = MODE_65816;
-	mx = 0x00;
 
 	if (s == "M65816")
 	{
@@ -1377,7 +1376,10 @@ void CLASS::initpass(void)
 	else
 	{
 		printf("Unknown CPU type in .ini\n");
+		mx=0x00;
 	}
+	mx = getInt("asm.startmx",mx);;
+
 	relocatable = false;
 	currentsym = NULL;
 	currentsymstr="";
diff --git a/opcodes.cpp b/opcodes.cpp
index 38bddf5..1140438 100644
--- a/opcodes.cpp
+++ b/opcodes.cpp
@@ -576,6 +576,10 @@ int CLASS::doBase6502(MerlinLine & line, TSymbol & sym)
 					bytelen++;
 				}
 			}
+			if ( ((m==syn_absx) || (m==syn_diix))  && ((sym.opcode==4) || (sym.opcode==5)))  // these are STX,LDX
+			{
+				err=true;
+			}
 			if ((m == syn_absx) || (m == syn_abs) || (m == syn_absy))
 			{
 				if ((line.flags & FLAG_FORCEABS) || (line.expr_value >= 0x100))
@@ -829,7 +833,7 @@ void CLASS::insertOpcodes(void)
 	pushopcode("BNE", 0x03, 0, OPHANDLER(&CLASS::doBRANCH));
 	pushopcode("BPL", 0x00, 0, OPHANDLER(&CLASS::doBRANCH));
 	pushopcode("BRA", 0x40, 0, OPHANDLER(&CLASS::doBRANCH));
-	pushopcode("BRK", 0x00, 0, OPHANDLER(&CLASS::doBYTE));
+	pushopcode("BRK", 0x00, 1, OPHANDLER(&CLASS::doAddress));
 	pushopcode("BRL", 0x20, 0, OPHANDLER(&CLASS::doBRANCH));
 	pushopcode("BVC", 0x01, 0, OPHANDLER(&CLASS::doBRANCH));
 	pushopcode("BVS", 0x81, 0, OPHANDLER(&CLASS::doBRANCH));
diff --git a/qasm.ini b/qasm.ini
index a0e4d4a..78c0ba2 100644
--- a/qasm.ini
+++ b/qasm.ini
@@ -21,7 +21,8 @@ path5=dirpath5
 
 [asm]
 casesen=true
-showmx=false
+showmx=true
+startmx=3
 lst=true
 ; can be M6502, M65C02, M65816
 cpu=M65816