After the PCBA was made, parameters related with the product such as the software version, the place it would be sold to were written successfully into the flash along with the software in the flash station . But after the PCBA assembled, the parameters were found lost. I don't know why. It's about software's problem or flash's problem?
We are now producing a DECT handset. After the PCBA of the handset were made, the parameters related with the product such as the software version, the place the product it would be sold to were written successfully into the flash(a kind of IC) along with the software in the flash station. Then in the assembly station, a complete handset was made. But then we found the parameters that had been written successfully into the flash were found lost(40% lost rate). We could not read the parameter from the handset(it's not the reader's problem). I don't know what happened in the handset. Who can tell me why the parameters were lost?
You haven't given us a lot of information, so this is a really wild guess.
I had a similar problem. I found that a PIC was overwriting some data. When the circuit was incomplete, the input signal to an inverter was changing too slowly. That made the output oscillate at very high speed instead of changing once.
The high speed oscillation was on the clock signal to the PIC, and clocking it to fast meant that it didn't work correctly and it erased its EEPROM.
If you can show us some circuit diagrams it would help.