Phalcon cannot update model when use phalcon 2

hi all, i found a bug, when i use phalcon 1.3.4, phalcon model->update() is work!, but, when i try upgrade my phalcon to 2.0.3, phalcon model->update() cant work properly, but, if i try model->save(), it's work...

This is fixed in the 2.0.x branch