bit corruption in Atmel AT89C51ED2 internal flash

hi working with AT89C51ED2 device from Atmel, has anyone encountered a situation in which a single or multiple bit of the internal flash image file get corrupted? i need a few hints on this phenomena...
bit corruption in Atmel AT89C51ED2 internal flash

hi working with AT89C51ED2 device from Atmel, has anyone encountered a situation in which a single or multiple bit of the internal flash image file get corrupted? i need a few hints on this phenomena...
AT89C51ED2: Selecting external vs internal flash

I would like to set a (fuse?) bit to select the external Flash/PEROM as program memory instead of default Flash internal to the AT89C51. Is the BLJB bit the one I want to set? How do I set it?
AT89C51ED2: Selecting external vs internal flash

I would like to set a (fuse?) bit to select the external Flash/PEROM as program memory instead of default Flash internal to the AT89C51. Is the BLJB bit the one I want to set? How do I set it?
Code Run from external flash with AT89C51ED2

Dear All, I'm facing some issue with executing code from external flash in AT89C51ED2 based controller card. I made EA/ pin GND, but its not executing.... The help greatly appreciated......