diff --git a/src/main/resources/assets/opencomputers/loot/openos/lib/core/full_text.lua b/src/main/resources/assets/opencomputers/loot/openos/lib/core/full_text.lua
index 0f982fa1c..72e55683b 100644
--- a/src/main/resources/assets/opencomputers/loot/openos/lib/core/full_text.lua
+++ b/src/main/resources/assets/opencomputers/loot/openos/lib/core/full_text.lua
@@ -181,7 +181,7 @@ function text.internal.reader(txt, mode)
   }, {__index=text.internal.stream_base((mode or ""):match("b"))})
   process.closeOnExit(reader)
 
-  return require("buffer").new((mode:match("[rb]+") or "r"), reader)
+  return require("buffer").new((mode or "r"):match("[rb]+"), reader)
 end
 
 function text.internal.writer(ostream, mode, append_txt)
@@ -223,7 +223,7 @@ function text.internal.writer(ostream, mode, append_txt)
   }, {__index=text.internal.stream_base((mode or ""):match("b"))})
   process.closeOnExit(writer)
 
-  return require("buffer").new((mode:match("[awb]+") or "w"), writer)
+  return require("buffer").new((mode or "w"):match("[awb]+"), writer)
 end
 
 function text.detab(value, tabWidth)
diff --git a/src/main/resources/assets/opencomputers/loot/openos/lib/io.lua b/src/main/resources/assets/opencomputers/loot/openos/lib/io.lua
index 1a6f25ce7..b6ff97116 100644
--- a/src/main/resources/assets/opencomputers/loot/openos/lib/io.lua
+++ b/src/main/resources/assets/opencomputers/loot/openos/lib/io.lua
@@ -47,17 +47,12 @@ end
 
 function io.stream(fd,file,mode)
   checkArg(1,fd,'number')
+  checkArg(2, file, "table", "string", "nil")
   assert(fd>=0,'fd must be >= 0. 0 is input, 1 is stdout, 2 is stderr')
   local dio = require("process").info().data.io
   if file then
     if type(file) == "string" then
-      local result, reason = io.open(file, mode)
-      if not result then
-        error(reason, 2)
-      end
-      file = result
-    elseif not io.type(file) then
-      error("bad argument #1 (string or file expected, got " .. type(file) .. ")", 2)
+      file = assert(io.open(file, mode))
     end
     dio[fd] = file
   end