This could be caused by a bad solder connection / short. Check if you can alter the behave by stressing the board by bending, pressing on the chip with a finger or tool etc.
yes we have done that but still the issue is same.
We have tried replacing the IC also but than also there is same issue.
Can you verify if the AC timing specs are satisfied. Especially, you are using a part with VIO option which requires longer page access time (tPACC=25ns).
Now after long debugging we have verified that pulling the Chip select signal Low have no issue, the processor boots easily from the flash but if the Chip select is kept high and processor pulls it low then the processor is not able to boot from the flash at -5 degree C.
Also the same behavior comes sometimes at room temperature also.
Need urgent support for this, if possible can you please connect to local Phone support who can help us to debug the issue on priority,