diff --git a/android/assets/jsons/Techs.json b/android/assets/jsons/Techs.json
index 5ff3e679d9..290299ddd5 100644
--- a/android/assets/jsons/Techs.json
+++ b/android/assets/jsons/Techs.json
@@ -482,12 +482,12 @@
 				name:"Nanotechnology",
 				row:3,
 				prerequisites:["Robotics","Ecology"]
-			}
+			},
 			{
 				name:"Particle Physics",
 				row:4,
 				prerequisites:["Nuclear Fission"]
-			}
+			},
 			{
 				name:"Satellites",
 				row:5,
diff --git a/core/src/com/unciv/logic/GameInfo.kt b/core/src/com/unciv/logic/GameInfo.kt
index 1cb346c635..7c96abe348 100644
--- a/core/src/com/unciv/logic/GameInfo.kt
+++ b/core/src/com/unciv/logic/GameInfo.kt
@@ -91,7 +91,7 @@ class GameInfo {
             tile = viableTiles.getRandom()
         }
 
-        var allResearchedTechs = GameBasics.Technologies.keys
+        val allResearchedTechs = GameBasics.Technologies.keys.toMutableList()
         for (civ in civilizations.filter { !it.isBarbarianCivilization() && !it.isDefeated() }) {
             allResearchedTechs.retainAll(civ.tech.techsResearched)
         }