I have a 27c1001 chip made by ST.I was something right inside and i read it ok but i wnat to erase it.When i try write FF dont write and give me "Device verify faild at address 0x000000,device read 0x00,buffer is 0xff"After that i write 00 , but now i cant write anything and give same error message.The ic is PLCC32 and i use PLCC to DIP32 adaptor. Thank you.