Erase the SST27SF512/W27E257 steps on Enhanced Willem Programmer:
1. connecte USB and data cables. 2. run 0.97ja software 3. select device W27X256(Vpe 14V) from the device menu. 4. set the DIP switch based on the software indication. 5. remove the safety jumper from the programmer and press the right LED button to select W27C LED. 6. insert the W27E257 in programmer's ZIF socket. The location is displayed on the software, 7. click on Erase button from the software, and click OK on the information window. Then wait untill the anothe inofrmation winfow popup and click ok 8. put back the safety jumper on the programmer and let LET reset to default position. 9. click on the blank check button to confirm the chip been erased. 10.if the chip is blank, you are ready to write new data.