diff --git a/.github/workflows/build-plugin.yml b/.github/workflows/build-plugin.yml
index ec63601..961853e 100644
--- a/.github/workflows/build-plugin.yml
+++ b/.github/workflows/build-plugin.yml
@@ -2,7 +2,7 @@ name: Build VCV Rack Plugin
 on: [push, pull_request]
 
 env:
-  rack-sdk-version: 2.4.1
+  rack-sdk-version: 2.5.1
   rack-plugin-toolchain-dir: /home/build/rack-plugin-toolchain
 
 defaults:
diff --git a/src/MidiThing.cpp b/src/MidiThing.cpp
index 18340b5..c7a5b6e 100644
--- a/src/MidiThing.cpp
+++ b/src/MidiThing.cpp
@@ -485,10 +485,16 @@ struct LEDDisplay : LightWidget {
 
 		if (font && font->handle >= 0) {
 
-			std::string text = "?-?v";  // fallback if module not yet defined
+			std::string text;
 			if (module) {
 				text = module->cfgPortModeNames[module->getVoltageMode(row, col) + 1];
 			}
+			else {
+				// fallback if module not yet defined
+				const char* cfgPortModeNames[5] = {"0/10v", "-5/5v", "-10/0v", "0/8v", "0/5v"};
+				const int randomModeForDisplay = rack::random::u32() % 5;
+				text = cfgPortModeNames[randomModeForDisplay];
+			}
 			char buffer[numChars + 1];
 			int l = text.size();
 			if (l > numChars)