A method for operating a flash memory device includes applying a first program voltage Vp1 to a plurality of word lines of memory cells. Threshold voltages of the memory cells are measured to obtain a first threshold voltage distribution for the memory cells. A second program voltage Vp2 is applied to the word lines of the memory cells that had been programmed with the first program voltage Vp1. The threshold voltages of the memory cells that have been programmed with the second program voltage Vp2 are measured to obtain a second threshold voltage distribution for the memory cells. A determination is made whether or not the memory cells that have been programmed with the second program voltage have been programmed properly. If the memory cells are determined to have been programmed properly, then the second program voltage is defined as an ending bias for a programming operation. If the memory cells are determined not to have been programmed properly, the memory cells are programmed using a third program voltage that is higher than the second program voltage.