I accidentally deleted this message thread. The contents of the the original message and one reply follow:

From: Evandro Zilio de Souza
Subject: Onboard flash missing data (AT89S8252)
Date/Time: 2002-01-17 14:04:33

Dear sirs,
I have being problems using the onboard EEPROM and FLASH.
Same devices are returnning from the field with wrong data in it !

The inside code runs, but not perfectly.
After reload the program code by the SPI, it runs ok again.

I know about a errata with some revisions of this devices. (earlier than 'S')
But somebody could tell me more about this ?

Evandro

From: J. Guy
Email: J.Guy@TeamIST.com
Subject: RE: Onboard flash missing data (AT89S8252)
Date/Time: 2002-01-17 19:00:36
Host: cblmdm205-162-223-199.buckeye-express.com

I have found that if you write to the data flash with low Vcc, you can corrupt the code portion.

Deleted Message 18861

From: Jacek Bogusz
Subject: RE: Onboard flash missing data (AT89S8252)
Date/Time: 2002-01-18 02:50:22

Hi Evandro!
In the past we have disscused the same problem. This is hardware problem and if you change your microcontroler revision, it will work. Please use "search" button for details.
And you are right - some bytes from Flash and / or Eeprom memory could be damaged during microcontroler working.

Jacek