Only assign DEBUG to a no-op function if Dbg.is_on==false

reader.lua

@@ -217,8 +217,6 @@ function showusage()
 	return
 end
 
-DEBUG = function() end
-
 local argidx = 1
 while argidx <= #ARGV do
 	local arg = ARGV[argidx]
@@ -250,6 +248,10 @@ while argidx <= #ARGV do
 	end
 end
 
+if not Dbg.is_on then
+	DEBUG = function() end
+end
+
 if Device:hasNoKeyboard() then
 	-- remove menu item shortcut for K4
 	Menu.is_enable_shortcut = false