diff --git a/src/anbox/platform/sdl/platform.cpp b/src/anbox/platform/sdl/platform.cpp
index 9d7c1d57cb039a0ba50169653e8da992c69c4fad..bfc2646f50b1f46e20b4d0f1f4badd271021e4c5 100644
--- a/src/anbox/platform/sdl/platform.cpp
+++ b/src/anbox/platform/sdl/platform.cpp
@@ -311,7 +311,7 @@ void Platform::process_events() {
 }
 
 bool Platform::text_input_fliter(const char* text) {
-  return text[0] > 0x7f || (input_flag == 0 &&
+  return text[0] < 0 || (input_flag == 0 &&
           ((text[0] <= 'Z' && text[0] >= 'A') || (text[0] <= 'z' && text[0] >= 'a')));
 }