diff --git a/libraries/RC_Channel/RC_Channel.cpp b/libraries/RC_Channel/RC_Channel.cpp
index 04a96b0b5b..f3cecf7e4a 100644
--- a/libraries/RC_Channel/RC_Channel.cpp
+++ b/libraries/RC_Channel/RC_Channel.cpp
@@ -1798,7 +1798,7 @@ RC_Channel *RC_Channels::find_channel_for_option(const RC_Channel::AUX_FUNC opti
 // duplicate_options_exist - returns true if any options are duplicated
 bool RC_Channels::duplicate_options_exist()
 {
-    uint8_t auxsw_option_counts[256] = {};
+    uint8_t auxsw_option_counts[512] = {};
     for (uint8_t i=0; i<NUM_RC_CHANNELS; i++) {
         const RC_Channel *c = channel(i);
         if (c == nullptr) {