diff --git a/frontend/ui/reader/readercopt.lua b/frontend/ui/reader/readercopt.lua
index 34be8a747..79b0e53b5 100644
--- a/frontend/ui/reader/readercopt.lua
+++ b/frontend/ui/reader/readercopt.lua
@@ -23,14 +23,17 @@ function ReaderCoptListener:onReadSettings(config)
 	local copt_font_size = config:readSetting("copt_font_size")
 	if copt_font_size then
 		table.insert(self.ui.postInitCallback, function()
-		    self.ui:handleEvent(Event:new("SetFontSize", copt_font_size))
+		    self.ui.document:setFontSize(copt_font_size)
+			self.ui:handleEvent(Event:new("UpdatePos"))
 		end)
 	end
 	
 	local copt_margins = config:readSetting("copt_page_margins")
 	if copt_margins then
 		table.insert(self.ui.postInitCallback, function()
-		    self.ui:handleEvent(Event:new("SetPageMargins", copt_margins))
+			-- FIXME: SetPageMargins will mess up current reading position
+			-- for now we simply disable this feature.
+		    --self.ui:handleEvent(Event:new("SetPageMargins", copt_margins))
 		end)
 	end
 end
diff --git a/koreader-base b/koreader-base
index 15b4d4a59..dc497096c 160000
--- a/koreader-base
+++ b/koreader-base
@@ -1 +1 @@
-Subproject commit 15b4d4a59c96afd5a6d0ec2f2b5cb5538628638c
+Subproject commit dc497096c0d39e1d9298ffe368960c5b838d4524