Apparently, 248Kb 11/70 configurations are not normal (diagnostic EKBEE1 complains), so all those machine configs have been bumped to 256Kb

modules/pdp11/lib/cpustate.js

@@ -262,6 +262,19 @@ CPUStatePDP11.prototype.resetMMU = function()
     if (this.bus) this.setMemoryAccess();
 };
 
+/**
+ * getMMUState()
+ *
+ * Returns bit 0 set if 22-bit, bit 1 set if 18-bit, or bit 2 set if 16-bit; used by the Panel component.
+ *
+ * @this {CPUStatePDP11}
+ * @return {number}
+ */
+CPUStatePDP11.prototype.getMMUState = function()
+{
+    return this.mmuEnable? ((this.regMMR3 & PDP11.MMR3.MMU_22BIT)? 1 : 2) : 4;
+};
+
 /**
  * setMemoryAccess()
  *