if you press and hold the - and + button does it lock those keys?
I can't get mine to do a firmware update but oh well I only use watts anyways, also at times my fire button sticks (I gave up with the place I bought mine from, I sent them a video of it, pics of the warranty and stuff...but they keep stalling asking for another pic or that the pics I sent were blurry, they weren't....oh well)