so i've been looking for the longest to check for ota without having to go though the hassle of going completely stock. so here is my way around this. using "wanam xposed" under security hacks is an option "fake system status" select that option. next with triangle away reset your flash counter if not already done then select "system modified workaround" this will disable supersu temporarily after reboot. now reboot the phone and you should have an official status, and are able to check for updates. after a few minutes supersu will turn on and your phone will still say official.i am using rooted stock metro firmware with cwm custom recovery.