diff --git a/src/main/resources/assets/opencomputers/lua/rom/boot/01_os.lua b/src/main/resources/assets/opencomputers/lua/rom/boot/01_os.lua
index 0d2eb25d5..8f89eb9b4 100644
--- a/src/main/resources/assets/opencomputers/lua/rom/boot/01_os.lua
+++ b/src/main/resources/assets/opencomputers/lua/rom/boot/01_os.lua
@@ -37,13 +37,16 @@ end
 
 function os.setenv(varname, value)
   checkArg(1, varname, "string", "number")
-  if value == nil then env[varname] = nil
-  local success, val = pcall(tostring, value)
-  if success then
-    env[varname] = val
-    return env[varname]
+  if value == nil then
+    env[varname] = nil
   else
-    return nil, val
+    local success, val = pcall(tostring, value)
+    if success then
+      env[varname] = val
+      return env[varname]
+    else
+      return nil, val
+    end
   end
 end