diff --git a/packages/core/src/config/config.ts b/packages/core/src/config/config.ts
index 241de0d04f..4677ef155e 100644
--- a/packages/core/src/config/config.ts
+++ b/packages/core/src/config/config.ts
@@ -951,8 +951,7 @@ export class Config {
   }
 
   activateFallbackMode(model: string): void {
-    this.setActiveModel(model);
-    coreEvents.emitModelChanged(model);
+    this.setModel(model, true);
     const authType = this.getContentGeneratorConfig()?.authType;
     if (authType) {
       logFlashFallback(this, new FlashFallbackEvent(authType));
diff --git a/packages/core/src/config/flashFallback.test.ts b/packages/core/src/config/flashFallback.test.ts
index 96adf37655..320d69c565 100644
--- a/packages/core/src/config/flashFallback.test.ts
+++ b/packages/core/src/config/flashFallback.test.ts
@@ -65,12 +65,9 @@ describe('Flash Model Fallback Configuration', () => {
   });
 
   describe('activateFallbackMode', () => {
-    it('should set active model to fallback and log event', () => {
+    it('should set model to fallback and log event', () => {
       config.activateFallbackMode(DEFAULT_GEMINI_FLASH_MODEL);
-      expect(config.getActiveModel()).toBe(DEFAULT_GEMINI_FLASH_MODEL);
-      // Ensure the persisted model setting is NOT changed (to preserve AUTO behavior)
-      expect(config.getModel()).toBe(DEFAULT_GEMINI_MODEL);
-
+      expect(config.getModel()).toBe(DEFAULT_GEMINI_FLASH_MODEL);
       expect(logFlashFallback).toHaveBeenCalledWith(
         config,
         expect.any(FlashFallbackEvent),