diff --git a/tracker/agb-tracker/src/lib.rs b/tracker/agb-tracker/src/lib.rs
index f729868f..834f702d 100644
--- a/tracker/agb-tracker/src/lib.rs
+++ b/tracker/agb-tracker/src/lib.rs
@@ -375,12 +375,14 @@ impl TrackerChannel {
                 PatternEffect::TonePortamento(amount, target) => {
                     channel.volume(self.volume.try_change_base().unwrap());
 
-                    if *amount < 1.into() {
-                        self.base_speed =
-                            (self.base_speed * amount.change_base()).max(target.change_base());
-                    } else {
-                        self.base_speed =
-                            (self.base_speed * amount.change_base()).min(target.change_base());
+                    if tick != 0 {
+                        if *amount < 1.into() {
+                            self.base_speed =
+                                (self.base_speed * amount.change_base()).max(target.change_base());
+                        } else {
+                            self.base_speed =
+                                (self.base_speed * amount.change_base()).min(target.change_base());
+                        }
                     }
 
                     channel.playback(self.base_speed.change_base());
diff --git a/tracker/agb-xm-core/src/lib.rs b/tracker/agb-xm-core/src/lib.rs
index c4f196f3..4396293c 100644
--- a/tracker/agb-xm-core/src/lib.rs
+++ b/tracker/agb-xm-core/src/lib.rs
@@ -469,7 +469,7 @@ fn note_to_frequency_amega(note: Note, fine_tune: f64, relative_note: i8) -> f64
     let note = (note as usize)
         .checked_add_signed(relative_note as isize)
         .expect("Note gone negative");
-    let pos = (note % 12) * 8 + (fine_tune / 16.0) as usize;
+    let pos = ((note % 12) * 8 + (fine_tune / 16.0) as usize).min(AMEGA_FREQUENCIES.len() - 2);
     let frac = (fine_tune / 16.0) - (fine_tune / 16.0).floor();
 
     let period = ((AMEGA_FREQUENCIES[pos] as f64 * (1.0 - frac))