diff --git a/lib/efi_loader/efi_capsule.c b/lib/efi_loader/efi_capsule.c
index d5d3ede..7a6f195 100644
--- a/lib/efi_loader/efi_capsule.c
+++ b/lib/efi_loader/efi_capsule.c
@@ -404,12 +404,6 @@
 
 	return status;
 }
-#else
-efi_status_t efi_capsule_authenticate(const void *capsule, efi_uintn_t capsule_size,
-				      void **image, efi_uintn_t *image_size)
-{
-	return EFI_UNSUPPORTED;
-}
 #endif /* CONFIG_EFI_CAPSULE_AUTHENTICATE */
 
 static __maybe_unused bool fwu_empty_capsule(struct efi_capsule_header *capsule)