diff --git a/src/option_window.rs b/src/option_window.rs
index 3933b16..6ad4f78 100644
--- a/src/option_window.rs
+++ b/src/option_window.rs
@@ -19,6 +19,7 @@ pub struct OptionWindow {
     category: OptionsCategory,
     card_options: Vec<(&'static Type, Box<dyn SettingsUi>)>,
     select_idx: Option<usize>,
+    allow_changing_cards: bool,
 }
 
 #[derive(PartialEq, Eq)]
@@ -41,13 +42,16 @@ impl OptionWindow {
             category: OptionsCategory::General,
             card_options,
             select_idx,
+            allow_changing_cards: !state.power(),
         }
     }
 
     fn sync_settings(&self, state: &mut EmuState) {
         state.update_options(self.options);
-        let cards = self.card_options.iter().map(|(typ, settings_ui)| (*typ, typ.new_card(ron::from_str(&settings_ui.serialize_settings()).unwrap()).unwrap())).collect();
-        state.set_cards(cards);
+        if self.allow_changing_cards {
+            let cards = self.card_options.iter().map(|(typ, settings_ui)| (*typ, typ.new_card(ron::from_str(&settings_ui.serialize_settings()).unwrap()).unwrap())).collect();
+            state.set_cards(cards);
+        }
     }
 }
 
@@ -69,6 +73,7 @@ impl Window for OptionWindow {
                 }
                 OptionsCategory::Cards => {
                     TopBottomPanel::top("card_opts").show_inside(ui, |ui| {
+                        ui.set_enabled(self.allow_changing_cards);
                         SidePanel::left("card_opts_left")
                             .show_separator_line(false)
                             .show_inside(ui, |ui| {
diff --git a/src/state.rs b/src/state.rs
index 97fe804..857caf1 100644
--- a/src/state.rs
+++ b/src/state.rs
@@ -229,6 +229,10 @@ impl EmuState {
         self.cards.iter().map(|(typ, card)| (typ.name().to_string(), card.get_settings())).collect()
     }
 
+    pub fn power(&self) -> bool {
+        self.fp_state.power()
+    }
+
     fn read_mem(&mut self, address: u16) -> u8 {
         self.cards.iter_mut().find_map(|(_, card)| card.read_mem(address)).unwrap_or(0xFF)
     }