diff --git a/SourceGen/AsmGen/AsmCc65.cs b/SourceGen/AsmGen/AsmCc65.cs
index 96ebdab..09dcbfc 100644
--- a/SourceGen/AsmGen/AsmCc65.cs
+++ b/SourceGen/AsmGen/AsmCc65.cs
@@ -94,8 +94,9 @@ namespace SourceGen.AsmGen {
         /// </summary>
         private CommonUtil.Version mAsmVersion = CommonUtil.Version.NO_VERSION;
 
-        // We test against this in a few places.
+        // Interesting versions.
         private static CommonUtil.Version V2_17 = new CommonUtil.Version(2, 17);
+        private static CommonUtil.Version V2_18 = new CommonUtil.Version(2, 18);
 
 
         // Pseudo-op string constants.
@@ -145,15 +146,19 @@ namespace SourceGen.AsmGen {
                 // bug fixes.
                 mAsmVersion = asmVersion.Version;
             } else {
-                // No assembler installed.  Use 2.17.
-                mAsmVersion = V2_17;
-            }
-            if (mAsmVersion <= V2_17) {
-                // cc65 v2.17: https://github.com/cc65/cc65/issues/717
-                Quirks.BlockMoveArgsReversed = true;
-                // cc65 v2.17: https://github.com/cc65/cc65/issues/754
-                Quirks.NoPcRelBankWrap = true;
+                // No assembler installed.  Use 2.18.
+                mAsmVersion = V2_18;
             }
+
+            // cc65 v2.17: https://github.com/cc65/cc65/issues/717
+            // cc65 v2.18: https://github.com/cc65/cc65/issues/925
+            Quirks.BlockMoveArgsReversed = true;
+
+            // cc65 v2.17: https://github.com/cc65/cc65/issues/754
+            // still broken in v2.18
+            Quirks.NoPcRelBankWrap = true;
+
+            // Special handling for forward references to zero-page labels is required.
             Quirks.SinglePassAssembler = true;
 
             mWorkDirectory = workDirectory;
@@ -224,10 +229,9 @@ namespace SourceGen.AsmGen {
                     //        string.Format(Properties.Resources.GENERATED_FOR_LATEST, "cc65"));
                     //}
 
-                    // Currently generating code for v2.17.
                     OutputLine(SourceFormatter.FullLineCommentDelimiter +
                         string.Format(Res.Strings.GENERATED_FOR_VERSION_FMT,
-                        "cc65", V2_17,
+                        "cc65", V2_18,
                         AsmCc65.OPTIONS + " -C " + Path.GetFileName(cfgName)));
                 }
 
@@ -311,7 +315,7 @@ namespace SourceGen.AsmGen {
 
         // IGenerator
         public string ModifyOpcode(int offset, OpDef op) {
-            if ((op == OpDef.OpWDM_WDM) && mAsmVersion <= V2_17) {
+            if ((op == OpDef.OpWDM_WDM) && mAsmVersion < V2_18) {
                 // cc65 v2.17 doesn't support WDM, and assembles BRK <arg> to opcode $05.
                 // https://github.com/cc65/cc65/issues/715
                 // https://github.com/cc65/cc65/issues/716
diff --git a/SourceGen/SGTestData/Expected/1000-allops-value-65816_cc65.S b/SourceGen/SGTestData/Expected/1000-allops-value-65816_cc65.S
index bc57f59..cf4f432 100644
--- a/SourceGen/SGTestData/Expected/1000-allops-value-65816_cc65.S
+++ b/SourceGen/SGTestData/Expected/1000-allops-value-65816_cc65.S
@@ -86,7 +86,7 @@ L1089:   and     ($ff),y
          rti
 
 L10AB:   eor     ($ff,x)
-         .byte   $42,$ff
+         wdm     $ff
          eor     $ff,S
          .byte   $44,$ff,$fe
          eor     $ff
diff --git a/SourceGen/SGTestData/Expected/1001-allops-zero-65816_cc65.S b/SourceGen/SGTestData/Expected/1001-allops-zero-65816_cc65.S
index 4e2b707..67a4877 100644
--- a/SourceGen/SGTestData/Expected/1001-allops-zero-65816_cc65.S
+++ b/SourceGen/SGTestData/Expected/1001-allops-zero-65816_cc65.S
@@ -86,7 +86,7 @@ L1089:   and     ($00),y
          rti
 
 L10AB:   eor     ($00,x)
-         .byte   $42,$00
+         wdm     $00
          eor     $00,S
          .byte   $44,$00,$00
          eor     $00
diff --git a/SourceGen/SGTestData/Expected/2014-label-dp_cc65.S b/SourceGen/SGTestData/Expected/2014-label-dp_cc65.S
index 2882c84..0e81fb3 100644
--- a/SourceGen/SGTestData/Expected/2014-label-dp_cc65.S
+++ b/SourceGen/SGTestData/Expected/2014-label-dp_cc65.S
@@ -87,7 +87,7 @@ L1089:   and     (L0080),y
          rti
 
 L10AB:   eor     (L0080,x)
-         .byte   $42,$80
+         wdm     $80
          eor     $80,S
          .byte   $44,$83,$84
          eor     z:L0080
diff --git a/SourceGen/WpfGui/EditAppSettings.xaml b/SourceGen/WpfGui/EditAppSettings.xaml
index 2f77b10..08777f4 100644
--- a/SourceGen/WpfGui/EditAppSettings.xaml
+++ b/SourceGen/WpfGui/EditAppSettings.xaml
@@ -156,7 +156,7 @@ limitations under the License.
                                 <Button DockPanel.Dock="Right" Content="Browse..." Width="75"
                                         Margin="8,0,0,8" Click="AsmExeBrowseButton_Click"/>
                                 <TextBox Name="asmExePathTextBox" DockPanel.Dock="Left" Margin="0,0,0,8"
-                                         Text="C:\something"/>
+                                         Text="C:\something" TextChanged="AsmExePathTextBox_TextChanged"/>
                             </DockPanel>
 
                             <TextBlock Grid.Column="0" Grid.Row="2" Text="Column widths:"
diff --git a/SourceGen/WpfGui/EditAppSettings.xaml.cs b/SourceGen/WpfGui/EditAppSettings.xaml.cs
index 1e73908..42ee611 100644
--- a/SourceGen/WpfGui/EditAppSettings.xaml.cs
+++ b/SourceGen/WpfGui/EditAppSettings.xaml.cs
@@ -631,6 +631,16 @@ namespace SourceGen.WpfGui {
 
         }
 
+        private void AsmExePathTextBox_TextChanged(object sender, TextChangedEventArgs e) {
+            if (IsLoaded) {
+                // We don't really need to be updating AssemblerConfig every time they type
+                // a character, but it's fine.
+                AssemblerInfo asmInfo = (AssemblerInfo)asmConfigComboBox.SelectedItem;
+                AssemblerConfig.SetConfig(mSettings, asmInfo.AssemblerId, GetAsmConfigFromUi());
+                IsDirty = true;
+            }
+        }
+
         /// <summary>
         /// Creates a file dialog to search for a specific executable.
         /// </summary>